diff mbox series

[v1,1/2] LoongArch: KVM: Add lsx support

Message ID 20231115091921.85516-2-zhaotianrui@loongson.cn
State New
Headers
Series LoongArch: KVM: Add LSX,LASX support |

Commit Message

zhaotianrui Nov. 15, 2023, 9:19 a.m. UTC 
  This patch adds LSX support for LoongArch KVM. The LSX means
LoongArch 128-bits vector instruction.
There will be LSX exception in KVM when guest use the LSX
instruction. KVM will enable LSX and restore the vector
registers for guest then return to guest to continue running.


Signed-off-by: Tianrui Zhao <zhaotianrui@loongson.cn>
---
 arch/loongarch/include/asm/kvm_host.h |  6 ++++
 arch/loongarch/include/asm/kvm_vcpu.h | 12 +++++++
 arch/loongarch/kvm/exit.c             | 18 ++++++++++
 arch/loongarch/kvm/switch.S           | 22 +++++++++++++
 arch/loongarch/kvm/trace.h            |  4 ++-
 arch/loongarch/kvm/vcpu.c             | 47 +++++++++++++++++++++++++--
 6 files changed, 105 insertions(+), 4 deletions(-)

Comments

kernel test robot Nov. 15, 2023, 7:35 p.m. UTC | #1 
Hi Tianrui,

kernel test robot noticed the following build errors:

[auto build test ERROR on kvm/queue]
[also build test ERROR on linus/master v6.7-rc1 next-20231115]
[cannot apply to mst-vhost/linux-next kvm/linux-next]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Tianrui-Zhao/LoongArch-KVM-Add-lsx-support/20231115-173658
base:   https://git.kernel.org/pub/scm/virt/kvm/kvm.git queue
patch link:    https://lore.kernel.org/r/20231115091921.85516-2-zhaotianrui%40loongson.cn
patch subject: [PATCH v1 1/2] LoongArch: KVM: Add lsx support
config: loongarch-allmodconfig (https://download.01.org/0day-ci/archive/20231116/202311160322.46CT0b8t-lkp@intel.com/config)
compiler: loongarch64-linux-gcc (GCC) 13.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20231116/202311160322.46CT0b8t-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202311160322.46CT0b8t-lkp@intel.com/

All errors (new ones prefixed by >>):

   arch/loongarch/kvm/switch.S: Assembler messages:
>> arch/loongarch/kvm/switch.S:68: Error: no match insn: la.pcrel	,1f
   arch/loongarch/kvm/switch.S:259:  Info: macro invoked from here
>> arch/loongarch/kvm/switch.S:69: Error: no match insn: alsl.d	,$r13,,3
   arch/loongarch/kvm/switch.S:259:  Info: macro invoked from here
>> arch/loongarch/kvm/switch.S:70: Error: no match insn: jr	
   arch/loongarch/kvm/switch.S:259:  Info: macro invoked from here


vim +68 arch/loongarch/kvm/switch.S

39fdf4be72f2b8 Tianrui Zhao 2023-10-02   43  
39fdf4be72f2b8 Tianrui Zhao 2023-10-02   44  /*
39fdf4be72f2b8 Tianrui Zhao 2023-10-02   45   * Prepare switch to guest, save host regs and restore guest regs.
39fdf4be72f2b8 Tianrui Zhao 2023-10-02   46   * a2: kvm_vcpu_arch, don't touch it until 'ertn'
39fdf4be72f2b8 Tianrui Zhao 2023-10-02   47   * t0, t1: temp register
39fdf4be72f2b8 Tianrui Zhao 2023-10-02   48   */
39fdf4be72f2b8 Tianrui Zhao 2023-10-02   49  .macro kvm_switch_to_guest
39fdf4be72f2b8 Tianrui Zhao 2023-10-02   50  	/* Set host ECFG.VS=0, all exceptions share one exception entry */
39fdf4be72f2b8 Tianrui Zhao 2023-10-02   51  	csrrd		t0, LOONGARCH_CSR_ECFG
39fdf4be72f2b8 Tianrui Zhao 2023-10-02   52  	bstrins.w	t0, zero, CSR_ECFG_VS_SHIFT_END, CSR_ECFG_VS_SHIFT
39fdf4be72f2b8 Tianrui Zhao 2023-10-02   53  	csrwr		t0, LOONGARCH_CSR_ECFG
39fdf4be72f2b8 Tianrui Zhao 2023-10-02   54  
39fdf4be72f2b8 Tianrui Zhao 2023-10-02   55  	/* Load up the new EENTRY */
39fdf4be72f2b8 Tianrui Zhao 2023-10-02   56  	ld.d	t0, a2, KVM_ARCH_GEENTRY
39fdf4be72f2b8 Tianrui Zhao 2023-10-02   57  	csrwr	t0, LOONGARCH_CSR_EENTRY
39fdf4be72f2b8 Tianrui Zhao 2023-10-02   58  
39fdf4be72f2b8 Tianrui Zhao 2023-10-02   59  	/* Set Guest ERA */
39fdf4be72f2b8 Tianrui Zhao 2023-10-02   60  	ld.d	t0, a2, KVM_ARCH_GPC
39fdf4be72f2b8 Tianrui Zhao 2023-10-02   61  	csrwr	t0, LOONGARCH_CSR_ERA
39fdf4be72f2b8 Tianrui Zhao 2023-10-02   62  
39fdf4be72f2b8 Tianrui Zhao 2023-10-02   63  	/* Save host PGDL */
39fdf4be72f2b8 Tianrui Zhao 2023-10-02   64  	csrrd	t0, LOONGARCH_CSR_PGDL
39fdf4be72f2b8 Tianrui Zhao 2023-10-02   65  	st.d	t0, a2, KVM_ARCH_HPGD
39fdf4be72f2b8 Tianrui Zhao 2023-10-02   66  
39fdf4be72f2b8 Tianrui Zhao 2023-10-02   67  	/* Switch to kvm */
39fdf4be72f2b8 Tianrui Zhao 2023-10-02  @68  	ld.d	t1, a2, KVM_VCPU_KVM - KVM_VCPU_ARCH
39fdf4be72f2b8 Tianrui Zhao 2023-10-02  @69  
39fdf4be72f2b8 Tianrui Zhao 2023-10-02  @70  	/* Load guest PGDL */
39fdf4be72f2b8 Tianrui Zhao 2023-10-02   71  	li.w    t0, KVM_GPGD
39fdf4be72f2b8 Tianrui Zhao 2023-10-02   72  	ldx.d   t0, t1, t0
39fdf4be72f2b8 Tianrui Zhao 2023-10-02   73  	csrwr	t0, LOONGARCH_CSR_PGDL
39fdf4be72f2b8 Tianrui Zhao 2023-10-02   74  
39fdf4be72f2b8 Tianrui Zhao 2023-10-02   75  	/* Mix GID and RID */
39fdf4be72f2b8 Tianrui Zhao 2023-10-02   76  	csrrd		t1, LOONGARCH_CSR_GSTAT
39fdf4be72f2b8 Tianrui Zhao 2023-10-02   77  	bstrpick.w	t1, t1, CSR_GSTAT_GID_SHIFT_END, CSR_GSTAT_GID_SHIFT
39fdf4be72f2b8 Tianrui Zhao 2023-10-02   78  	csrrd		t0, LOONGARCH_CSR_GTLBC
39fdf4be72f2b8 Tianrui Zhao 2023-10-02   79  	bstrins.w	t0, t1, CSR_GTLBC_TGID_SHIFT_END, CSR_GTLBC_TGID_SHIFT
39fdf4be72f2b8 Tianrui Zhao 2023-10-02   80  	csrwr		t0, LOONGARCH_CSR_GTLBC
39fdf4be72f2b8 Tianrui Zhao 2023-10-02   81  
39fdf4be72f2b8 Tianrui Zhao 2023-10-02   82  	/*
39fdf4be72f2b8 Tianrui Zhao 2023-10-02   83  	 * Enable intr in root mode with future ertn so that host interrupt
39fdf4be72f2b8 Tianrui Zhao 2023-10-02   84  	 * can be responsed during VM runs
39fdf4be72f2b8 Tianrui Zhao 2023-10-02   85  	 * Guest CRMD comes from separate GCSR_CRMD register
39fdf4be72f2b8 Tianrui Zhao 2023-10-02   86  	 */
39fdf4be72f2b8 Tianrui Zhao 2023-10-02   87  	ori	t0, zero, CSR_PRMD_PIE
39fdf4be72f2b8 Tianrui Zhao 2023-10-02   88  	csrxchg	t0, t0,   LOONGARCH_CSR_PRMD
39fdf4be72f2b8 Tianrui Zhao 2023-10-02   89  
39fdf4be72f2b8 Tianrui Zhao 2023-10-02   90  	/* Set PVM bit to setup ertn to guest context */
39fdf4be72f2b8 Tianrui Zhao 2023-10-02   91  	ori	t0, zero, CSR_GSTAT_PVM
39fdf4be72f2b8 Tianrui Zhao 2023-10-02   92  	csrxchg	t0, t0,   LOONGARCH_CSR_GSTAT
39fdf4be72f2b8 Tianrui Zhao 2023-10-02   93  
39fdf4be72f2b8 Tianrui Zhao 2023-10-02   94  	/* Load Guest GPRs */
39fdf4be72f2b8 Tianrui Zhao 2023-10-02   95  	kvm_restore_guest_gprs a2
39fdf4be72f2b8 Tianrui Zhao 2023-10-02   96  	/* Load KVM_ARCH register */
39fdf4be72f2b8 Tianrui Zhao 2023-10-02   97  	ld.d	a2, a2,	(KVM_ARCH_GGPR + 8 * REG_A2)
39fdf4be72f2b8 Tianrui Zhao 2023-10-02   98  
39fdf4be72f2b8 Tianrui Zhao 2023-10-02   99  	ertn /* Switch to guest: GSTAT.PGM = 1, ERRCTL.ISERR = 0, TLBRPRMD.ISTLBR = 0 */
39fdf4be72f2b8 Tianrui Zhao 2023-10-02  100  .endm
39fdf4be72f2b8 Tianrui Zhao 2023-10-02  101  
39fdf4be72f2b8 Tianrui Zhao 2023-10-02  102  	/*
39fdf4be72f2b8 Tianrui Zhao 2023-10-02  103  	 * Exception entry for general exception from guest mode
39fdf4be72f2b8 Tianrui Zhao 2023-10-02  104  	 *  - IRQ is disabled
39fdf4be72f2b8 Tianrui Zhao 2023-10-02  105  	 *  - kernel privilege in root mode
39fdf4be72f2b8 Tianrui Zhao 2023-10-02  106  	 *  - page mode keep unchanged from previous PRMD in root mode
39fdf4be72f2b8 Tianrui Zhao 2023-10-02  107  	 *  - Fixme: tlb exception cannot happen since registers relative with TLB
39fdf4be72f2b8 Tianrui Zhao 2023-10-02  108  	 *  -        is still in guest mode, such as pgd table/vmid registers etc,
39fdf4be72f2b8 Tianrui Zhao 2023-10-02  109  	 *  -        will fix with hw page walk enabled in future
39fdf4be72f2b8 Tianrui Zhao 2023-10-02  110  	 * load kvm_vcpu from reserved CSR KVM_VCPU_KS, and save a2 to KVM_TEMP_KS
39fdf4be72f2b8 Tianrui Zhao 2023-10-02  111  	 */
39fdf4be72f2b8 Tianrui Zhao 2023-10-02  112  	.text
39fdf4be72f2b8 Tianrui Zhao 2023-10-02  113  	.cfi_sections	.debug_frame
39fdf4be72f2b8 Tianrui Zhao 2023-10-02  114  SYM_CODE_START(kvm_exc_entry)
39fdf4be72f2b8 Tianrui Zhao 2023-10-02  115  	csrwr	a2,   KVM_TEMP_KS
39fdf4be72f2b8 Tianrui Zhao 2023-10-02  116  	csrrd	a2,   KVM_VCPU_KS
39fdf4be72f2b8 Tianrui Zhao 2023-10-02  117  	addi.d	a2,   a2, KVM_VCPU_ARCH
39fdf4be72f2b8 Tianrui Zhao 2023-10-02  118  
39fdf4be72f2b8 Tianrui Zhao 2023-10-02  119  	/* After save GPRs, free to use any GPR */
39fdf4be72f2b8 Tianrui Zhao 2023-10-02  120  	kvm_save_guest_gprs a2
39fdf4be72f2b8 Tianrui Zhao 2023-10-02  121  	/* Save guest A2 */
39fdf4be72f2b8 Tianrui Zhao 2023-10-02  122  	csrrd	t0,	KVM_TEMP_KS
39fdf4be72f2b8 Tianrui Zhao 2023-10-02  123  	st.d	t0,	a2,	(KVM_ARCH_GGPR + 8 * REG_A2)
39fdf4be72f2b8 Tianrui Zhao 2023-10-02  124  
39fdf4be72f2b8 Tianrui Zhao 2023-10-02  125  	/* A2 is kvm_vcpu_arch, A1 is free to use */
39fdf4be72f2b8 Tianrui Zhao 2023-10-02  126  	csrrd	s1,   KVM_VCPU_KS
39fdf4be72f2b8 Tianrui Zhao 2023-10-02  127  	ld.d	s0,   s1, KVM_VCPU_RUN
39fdf4be72f2b8 Tianrui Zhao 2023-10-02  128  
39fdf4be72f2b8 Tianrui Zhao 2023-10-02  129  	csrrd	t0,   LOONGARCH_CSR_ESTAT
39fdf4be72f2b8 Tianrui Zhao 2023-10-02  130  	st.d	t0,   a2, KVM_ARCH_HESTAT
39fdf4be72f2b8 Tianrui Zhao 2023-10-02  131  	csrrd	t0,   LOONGARCH_CSR_ERA
39fdf4be72f2b8 Tianrui Zhao 2023-10-02  132  	st.d	t0,   a2, KVM_ARCH_GPC
39fdf4be72f2b8 Tianrui Zhao 2023-10-02  133  	csrrd	t0,   LOONGARCH_CSR_BADV
39fdf4be72f2b8 Tianrui Zhao 2023-10-02  134  	st.d	t0,   a2, KVM_ARCH_HBADV
39fdf4be72f2b8 Tianrui Zhao 2023-10-02  135  	csrrd	t0,   LOONGARCH_CSR_BADI
39fdf4be72f2b8 Tianrui Zhao 2023-10-02  136  	st.d	t0,   a2, KVM_ARCH_HBADI
39fdf4be72f2b8 Tianrui Zhao 2023-10-02  137  
39fdf4be72f2b8 Tianrui Zhao 2023-10-02  138  	/* Restore host ECFG.VS */
39fdf4be72f2b8 Tianrui Zhao 2023-10-02  139  	csrrd	t0, LOONGARCH_CSR_ECFG
39fdf4be72f2b8 Tianrui Zhao 2023-10-02  140  	ld.d	t1, a2, KVM_ARCH_HECFG
39fdf4be72f2b8 Tianrui Zhao 2023-10-02  141  	or	t0, t0, t1
39fdf4be72f2b8 Tianrui Zhao 2023-10-02  142  	csrwr	t0, LOONGARCH_CSR_ECFG
39fdf4be72f2b8 Tianrui Zhao 2023-10-02  143  
39fdf4be72f2b8 Tianrui Zhao 2023-10-02  144  	/* Restore host EENTRY */
39fdf4be72f2b8 Tianrui Zhao 2023-10-02  145  	ld.d	t0, a2, KVM_ARCH_HEENTRY
39fdf4be72f2b8 Tianrui Zhao 2023-10-02  146  	csrwr	t0, LOONGARCH_CSR_EENTRY
39fdf4be72f2b8 Tianrui Zhao 2023-10-02  147  
39fdf4be72f2b8 Tianrui Zhao 2023-10-02  148  	/* Restore host pgd table */
39fdf4be72f2b8 Tianrui Zhao 2023-10-02  149  	ld.d    t0, a2, KVM_ARCH_HPGD
39fdf4be72f2b8 Tianrui Zhao 2023-10-02  150  	csrwr   t0, LOONGARCH_CSR_PGDL
39fdf4be72f2b8 Tianrui Zhao 2023-10-02  151  
39fdf4be72f2b8 Tianrui Zhao 2023-10-02  152  	/*
39fdf4be72f2b8 Tianrui Zhao 2023-10-02  153  	 * Disable PGM bit to enter root mode by default with next ertn
39fdf4be72f2b8 Tianrui Zhao 2023-10-02  154  	 */
39fdf4be72f2b8 Tianrui Zhao 2023-10-02  155  	ori	t0, zero, CSR_GSTAT_PVM
39fdf4be72f2b8 Tianrui Zhao 2023-10-02  156  	csrxchg	zero, t0, LOONGARCH_CSR_GSTAT
39fdf4be72f2b8 Tianrui Zhao 2023-10-02  157  
39fdf4be72f2b8 Tianrui Zhao 2023-10-02  158  	/*
39fdf4be72f2b8 Tianrui Zhao 2023-10-02  159  	 * Clear GTLBC.TGID field
39fdf4be72f2b8 Tianrui Zhao 2023-10-02  160  	 *       0: for root  tlb update in future tlb instr
39fdf4be72f2b8 Tianrui Zhao 2023-10-02  161  	 *  others: for guest tlb update like gpa to hpa in future tlb instr
39fdf4be72f2b8 Tianrui Zhao 2023-10-02  162  	 */
39fdf4be72f2b8 Tianrui Zhao 2023-10-02  163  	csrrd	t0, LOONGARCH_CSR_GTLBC
39fdf4be72f2b8 Tianrui Zhao 2023-10-02  164  	bstrins.w	t0, zero, CSR_GTLBC_TGID_SHIFT_END, CSR_GTLBC_TGID_SHIFT
39fdf4be72f2b8 Tianrui Zhao 2023-10-02  165  	csrwr	t0, LOONGARCH_CSR_GTLBC
39fdf4be72f2b8 Tianrui Zhao 2023-10-02  166  	ld.d	tp, a2, KVM_ARCH_HTP
39fdf4be72f2b8 Tianrui Zhao 2023-10-02  167  	ld.d	sp, a2, KVM_ARCH_HSP
39fdf4be72f2b8 Tianrui Zhao 2023-10-02  168  	/* restore per cpu register */
39fdf4be72f2b8 Tianrui Zhao 2023-10-02  169  	ld.d	u0, a2, KVM_ARCH_HPERCPU
39fdf4be72f2b8 Tianrui Zhao 2023-10-02  170  	addi.d	sp, sp, -PT_SIZE
39fdf4be72f2b8 Tianrui Zhao 2023-10-02  171  
39fdf4be72f2b8 Tianrui Zhao 2023-10-02  172  	/* Prepare handle exception */
39fdf4be72f2b8 Tianrui Zhao 2023-10-02  173  	or	a0, s0, zero
39fdf4be72f2b8 Tianrui Zhao 2023-10-02  174  	or	a1, s1, zero
39fdf4be72f2b8 Tianrui Zhao 2023-10-02  175  	ld.d	t8, a2, KVM_ARCH_HANDLE_EXIT
39fdf4be72f2b8 Tianrui Zhao 2023-10-02  176  	jirl	ra, t8, 0
39fdf4be72f2b8 Tianrui Zhao 2023-10-02  177  
39fdf4be72f2b8 Tianrui Zhao 2023-10-02  178  	or	a2, s1, zero
39fdf4be72f2b8 Tianrui Zhao 2023-10-02  179  	addi.d	a2, a2, KVM_VCPU_ARCH
39fdf4be72f2b8 Tianrui Zhao 2023-10-02  180  
39fdf4be72f2b8 Tianrui Zhao 2023-10-02  181  	/* Resume host when ret <= 0 */
39fdf4be72f2b8 Tianrui Zhao 2023-10-02  182  	blez	a0, ret_to_host
39fdf4be72f2b8 Tianrui Zhao 2023-10-02  183  
39fdf4be72f2b8 Tianrui Zhao 2023-10-02  184  	/*
39fdf4be72f2b8 Tianrui Zhao 2023-10-02  185           * Return to guest
39fdf4be72f2b8 Tianrui Zhao 2023-10-02  186           * Save per cpu register again, maybe switched to another cpu
39fdf4be72f2b8 Tianrui Zhao 2023-10-02  187           */
39fdf4be72f2b8 Tianrui Zhao 2023-10-02  188  	st.d	u0, a2, KVM_ARCH_HPERCPU
39fdf4be72f2b8 Tianrui Zhao 2023-10-02  189  
39fdf4be72f2b8 Tianrui Zhao 2023-10-02  190  	/* Save kvm_vcpu to kscratch */
39fdf4be72f2b8 Tianrui Zhao 2023-10-02  191  	csrwr	s1, KVM_VCPU_KS
39fdf4be72f2b8 Tianrui Zhao 2023-10-02  192  	kvm_switch_to_guest
39fdf4be72f2b8 Tianrui Zhao 2023-10-02  193  
39fdf4be72f2b8 Tianrui Zhao 2023-10-02  194  ret_to_host:
39fdf4be72f2b8 Tianrui Zhao 2023-10-02  195  	ld.d    a2, a2, KVM_ARCH_HSP
39fdf4be72f2b8 Tianrui Zhao 2023-10-02  196  	addi.d  a2, a2, -PT_SIZE
39fdf4be72f2b8 Tianrui Zhao 2023-10-02  197  	kvm_restore_host_gpr    a2
39fdf4be72f2b8 Tianrui Zhao 2023-10-02  198  	jr      ra
39fdf4be72f2b8 Tianrui Zhao 2023-10-02  199
WANG Xuerui Nov. 16, 2023, 7:15 a.m. UTC | #2 
On 11/15/23 17:19, Tianrui Zhao wrote:
> This patch adds LSX support for LoongArch KVM. The LSX means
> LoongArch 128-bits vector instruction.
Maybe we don't need to explain what "LSX" is; people working on 
LoongArch kernel should already know this through the kernel docs and 
the various occurrences in the code.
> There will be LSX exception in KVM when guest use the LSX
> instruction. KVM will enable LSX and restore the vector
> registers for guest then return to guest to continue running.
>
One more extra line that should get removed.
> Signed-off-by: Tianrui Zhao <zhaotianrui@loongson.cn>
> ---
>   arch/loongarch/include/asm/kvm_host.h |  6 ++++
>   arch/loongarch/include/asm/kvm_vcpu.h | 12 +++++++
>   arch/loongarch/kvm/exit.c             | 18 ++++++++++
>   arch/loongarch/kvm/switch.S           | 22 +++++++++++++
>   arch/loongarch/kvm/trace.h            |  4 ++-
>   arch/loongarch/kvm/vcpu.c             | 47 +++++++++++++++++++++++++--
>   6 files changed, 105 insertions(+), 4 deletions(-)
>
> diff --git a/arch/loongarch/include/asm/kvm_host.h b/arch/loongarch/include/asm/kvm_host.h
> index 11328700d4..6c65c25169 100644
> --- a/arch/loongarch/include/asm/kvm_host.h
> +++ b/arch/loongarch/include/asm/kvm_host.h
> @@ -94,6 +94,7 @@ enum emulation_result {
>   #define KVM_LARCH_FPU		(0x1 << 0)
>   #define KVM_LARCH_SWCSR_LATEST	(0x1 << 1)
>   #define KVM_LARCH_HWCSR_USABLE	(0x1 << 2)
> +#define KVM_LARCH_LSX		(0x1 << 3)
>   
>   struct kvm_vcpu_arch {
>   	/*
> @@ -175,6 +176,11 @@ static inline void writel_sw_gcsr(struct loongarch_csrs *csr, int reg, unsigned
>   	csr->csrs[reg] = val;
>   }
>   
> +static inline bool kvm_guest_has_lsx(struct kvm_vcpu_arch *arch)
> +{
> +	return arch->cpucfg[2] & CPUCFG2_LSX;
> +}
> +
>   /* Debug: dump vcpu state */
>   int kvm_arch_vcpu_dump_regs(struct kvm_vcpu *vcpu);
>   
> diff --git a/arch/loongarch/include/asm/kvm_vcpu.h b/arch/loongarch/include/asm/kvm_vcpu.h
> index 553cfa2b2b..c629771e12 100644
> --- a/arch/loongarch/include/asm/kvm_vcpu.h
> +++ b/arch/loongarch/include/asm/kvm_vcpu.h
> @@ -55,6 +55,18 @@ void kvm_save_fpu(struct loongarch_fpu *fpu);
>   void kvm_restore_fpu(struct loongarch_fpu *fpu);
>   void kvm_restore_fcsr(struct loongarch_fpu *fpu);
>   
> +#ifdef CONFIG_CPU_HAS_LSX
> +void kvm_own_lsx(struct kvm_vcpu *vcpu);
> +void kvm_save_lsx(struct loongarch_fpu *fpu);
> +void kvm_restore_lsx(struct loongarch_fpu *fpu);
> +void kvm_restore_lsx_upper(struct loongarch_fpu *fpu);
> +#else
> +static inline void kvm_own_lsx(struct kvm_vcpu *vcpu) { }
> +static inline void kvm_save_lsx(struct loongarch_fpu *fpu) { }
> +static inline void kvm_restore_lsx(struct loongarch_fpu *fpu) { }
> +static inline void kvm_restore_lsx_upper(struct loongarch_fpu *fpu) { }
> +#endif
> +
>   void kvm_acquire_timer(struct kvm_vcpu *vcpu);
>   void kvm_init_timer(struct kvm_vcpu *vcpu, unsigned long hz);
>   void kvm_reset_timer(struct kvm_vcpu *vcpu);
> diff --git a/arch/loongarch/kvm/exit.c b/arch/loongarch/kvm/exit.c
> index ce8de3fa47..1b1c58ccc8 100644
> --- a/arch/loongarch/kvm/exit.c
> +++ b/arch/loongarch/kvm/exit.c
> @@ -659,6 +659,23 @@ static int kvm_handle_fpu_disabled(struct kvm_vcpu *vcpu)
>   	return RESUME_GUEST;
>   }
>   
> +/*
> + * kvm_handle_lsx_disabled() - Guest used LSX while disabled in root.
> + * @vcpu:      Virtual CPU context.
> + *
> + * Handle when the guest attempts to use LSX when it is disabled in the root
> + * context.
> + */
> +static int kvm_handle_lsx_disabled(struct kvm_vcpu *vcpu)
> +{
> +	if (!kvm_guest_has_lsx(&vcpu->arch))
> +		kvm_queue_exception(vcpu, EXCCODE_INE, 0);
> +	else
> +		kvm_own_lsx(vcpu);
> +
> +	return RESUME_GUEST;
> +}
> +
>   /*
>    * LoongArch KVM callback handling for unimplemented guest exiting
>    */
> @@ -687,6 +704,7 @@ static exit_handle_fn kvm_fault_tables[EXCCODE_INT_START] = {
>   	[EXCCODE_TLBS]			= kvm_handle_write_fault,
>   	[EXCCODE_TLBM]			= kvm_handle_write_fault,
>   	[EXCCODE_FPDIS]			= kvm_handle_fpu_disabled,
> +	[EXCCODE_LSXDIS]                = kvm_handle_lsx_disabled,
>   	[EXCCODE_GSPR]			= kvm_handle_gspr,
>   };
>   
> diff --git a/arch/loongarch/kvm/switch.S b/arch/loongarch/kvm/switch.S
> index 0ed9040307..32ba092a44 100644
> --- a/arch/loongarch/kvm/switch.S
> +++ b/arch/loongarch/kvm/switch.S
> @@ -245,6 +245,28 @@ SYM_FUNC_START(kvm_restore_fpu)
>   	jr                 ra
>   SYM_FUNC_END(kvm_restore_fpu)
>   
> +#ifdef CONFIG_CPU_HAS_LSX
> +SYM_FUNC_START(kvm_save_lsx)
> +	fpu_save_csr    a0 t1
> +	fpu_save_cc     a0 t1 t2
> +	lsx_save_data   a0 t1
> +	jirl            zero, ra, 0
"jr ra" for consistency (e.g. with the function immediately above); 
similarly for other such usages.
> +SYM_FUNC_END(kvm_save_lsx)
> +
> +SYM_FUNC_START(kvm_restore_lsx)
> +	lsx_restore_data a0 t1
> +	fpu_restore_cc   a0 t1 t2
> +	fpu_restore_csr  a0 t1
> +	jirl             zero, ra, 0
> +SYM_FUNC_END(kvm_restore_lsx)
> +
> +SYM_FUNC_START(kvm_restore_lsx_upper)
> +	lsx_restore_all_upper a0 t0 t1
> +
> +	jirl                  zero, ra, 0
> +SYM_FUNC_END(kvm_restore_lsx_upper)
> +#endif
> +
>   	.section ".rodata"
>   SYM_DATA(kvm_exception_size, .quad kvm_exc_entry_end - kvm_exc_entry)
>   SYM_DATA(kvm_enter_guest_size, .quad kvm_enter_guest_end - kvm_enter_guest)
> diff --git a/arch/loongarch/kvm/trace.h b/arch/loongarch/kvm/trace.h
> index a1e35d6554..7da4e230e8 100644
> --- a/arch/loongarch/kvm/trace.h
> +++ b/arch/loongarch/kvm/trace.h
> @@ -102,6 +102,7 @@ TRACE_EVENT(kvm_exit_gspr,
>   #define KVM_TRACE_AUX_DISCARD		4
>   
>   #define KVM_TRACE_AUX_FPU		1
> +#define KVM_TRACE_AUX_LSX		2
>   
>   #define kvm_trace_symbol_aux_op				\
>   	{ KVM_TRACE_AUX_SAVE,		"save" },	\
> @@ -111,7 +112,8 @@ TRACE_EVENT(kvm_exit_gspr,
>   	{ KVM_TRACE_AUX_DISCARD,	"discard" }
>   
>   #define kvm_trace_symbol_aux_state			\
> -	{ KVM_TRACE_AUX_FPU,     "FPU" }
> +	{ KVM_TRACE_AUX_FPU,     "FPU" },		\
> +	{ KVM_TRACE_AUX_LSX,     "LSX" }
>   
>   TRACE_EVENT(kvm_aux,
>   	    TP_PROTO(struct kvm_vcpu *vcpu, unsigned int op,
> diff --git a/arch/loongarch/kvm/vcpu.c b/arch/loongarch/kvm/vcpu.c
> index 73d0c2b9c1..f0bb583353 100644
> --- a/arch/loongarch/kvm/vcpu.c
> +++ b/arch/loongarch/kvm/vcpu.c
> @@ -378,9 +378,13 @@ static int kvm_set_one_reg(struct kvm_vcpu *vcpu,
>   		break;
>   	case KVM_REG_LOONGARCH_CPUCFG:
>   		id = KVM_GET_IOC_CPUCFG_IDX(reg->id);
> -		if (id >= 0 && id < KVM_MAX_CPUCFG_REGS)
> +		if (id >= 0 && id < KVM_MAX_CPUCFG_REGS) {
>   			vcpu->arch.cpucfg[id] = (u32)v;
> -		else
> +			if (id == 2 && v & CPUCFG2_LSX && !cpu_has_lsx) {
> +				vcpu->arch.cpucfg[id] &= ~CPUCFG2_LSX;
> +				ret = -EINVAL;
> +			}
> +		} else
>   			ret = -EINVAL;
>   		break;
>   	case KVM_REG_LOONGARCH_KVM:
> @@ -561,12 +565,49 @@ void kvm_own_fpu(struct kvm_vcpu *vcpu)
>   	preempt_enable();
>   }
>   
> +#ifdef CONFIG_CPU_HAS_LSX
> +/* Enable LSX for guest and restore context */
> +void kvm_own_lsx(struct kvm_vcpu *vcpu)
> +{
> +	preempt_disable();
> +
> +	/* Enable LSX for guest */
> +	set_csr_euen(CSR_EUEN_LSXEN | CSR_EUEN_FPEN);
> +	switch (vcpu->arch.aux_inuse & KVM_LARCH_FPU) {
> +	case KVM_LARCH_FPU:
> +		/*
> +		 * Guest FPU state already loaded,
> +		 * only restore upper LSX state
> +		 */
> +		kvm_restore_lsx_upper(&vcpu->arch.fpu);
> +		break;
> +	default:
> +		/* Neither FP or LSX already active,
> +		 * restore full LSX state
> +		 */
> +		kvm_restore_lsx(&vcpu->arch.fpu);
> +	break;
> +	}
> +
> +	trace_kvm_aux(vcpu, KVM_TRACE_AUX_RESTORE, KVM_TRACE_AUX_LSX);
> +	vcpu->arch.aux_inuse |= KVM_LARCH_LSX | KVM_LARCH_FPU;
> +	preempt_enable();
> +}
> +#endif
> +
>   /* Save context and disable FPU */
>   void kvm_lose_fpu(struct kvm_vcpu *vcpu)
>   {
>   	preempt_disable();
>   
> -	if (vcpu->arch.aux_inuse & KVM_LARCH_FPU) {
> +	if (vcpu->arch.aux_inuse & KVM_LARCH_LSX) {
> +		kvm_save_lsx(&vcpu->arch.fpu);
> +		vcpu->arch.aux_inuse &= ~(KVM_LARCH_LSX | KVM_LARCH_FPU);
> +		trace_kvm_aux(vcpu, KVM_TRACE_AUX_SAVE, KVM_TRACE_AUX_LSX);
> +
> +		/* Disable LSX & FPU */
> +		clear_csr_euen(CSR_EUEN_FPEN | CSR_EUEN_LSXEN);
> +	} else if (vcpu->arch.aux_inuse & KVM_LARCH_FPU) {
>   		kvm_save_fpu(&vcpu->arch.fpu);
>   		vcpu->arch.aux_inuse &= ~KVM_LARCH_FPU;
>   		trace_kvm_aux(vcpu, KVM_TRACE_AUX_SAVE, KVM_TRACE_AUX_FPU);
maobibo Nov. 17, 2023, 8:24 a.m. UTC | #3 
On 2023/11/15 下午5:19, Tianrui Zhao wrote:
> This patch adds LSX support for LoongArch KVM. The LSX means
> LoongArch 128-bits vector instruction.
> There will be LSX exception in KVM when guest use the LSX
> instruction. KVM will enable LSX and restore the vector
> registers for guest then return to guest to continue running.
> 
> 
> Signed-off-by: Tianrui Zhao <zhaotianrui@loongson.cn>
> ---
>   arch/loongarch/include/asm/kvm_host.h |  6 ++++
>   arch/loongarch/include/asm/kvm_vcpu.h | 12 +++++++
>   arch/loongarch/kvm/exit.c             | 18 ++++++++++
>   arch/loongarch/kvm/switch.S           | 22 +++++++++++++
>   arch/loongarch/kvm/trace.h            |  4 ++-
>   arch/loongarch/kvm/vcpu.c             | 47 +++++++++++++++++++++++++--
>   6 files changed, 105 insertions(+), 4 deletions(-)
> 
> diff --git a/arch/loongarch/include/asm/kvm_host.h b/arch/loongarch/include/asm/kvm_host.h
> index 11328700d4..6c65c25169 100644
> --- a/arch/loongarch/include/asm/kvm_host.h
> +++ b/arch/loongarch/include/asm/kvm_host.h
> @@ -94,6 +94,7 @@ enum emulation_result {
>   #define KVM_LARCH_FPU		(0x1 << 0)
>   #define KVM_LARCH_SWCSR_LATEST	(0x1 << 1)
>   #define KVM_LARCH_HWCSR_USABLE	(0x1 << 2)
> +#define KVM_LARCH_LSX		(0x1 << 3)
>   
>   struct kvm_vcpu_arch {
>   	/*
> @@ -175,6 +176,11 @@ static inline void writel_sw_gcsr(struct loongarch_csrs *csr, int reg, unsigned
>   	csr->csrs[reg] = val;
>   }
>   
> +static inline bool kvm_guest_has_lsx(struct kvm_vcpu_arch *arch)
> +{
> +	return arch->cpucfg[2] & CPUCFG2_LSX;
> +}
> +
>   /* Debug: dump vcpu state */
>   int kvm_arch_vcpu_dump_regs(struct kvm_vcpu *vcpu);
>   
> diff --git a/arch/loongarch/include/asm/kvm_vcpu.h b/arch/loongarch/include/asm/kvm_vcpu.h
> index 553cfa2b2b..c629771e12 100644
> --- a/arch/loongarch/include/asm/kvm_vcpu.h
> +++ b/arch/loongarch/include/asm/kvm_vcpu.h
> @@ -55,6 +55,18 @@ void kvm_save_fpu(struct loongarch_fpu *fpu);
>   void kvm_restore_fpu(struct loongarch_fpu *fpu);
>   void kvm_restore_fcsr(struct loongarch_fpu *fpu);
>   
> +#ifdef CONFIG_CPU_HAS_LSX
> +void kvm_own_lsx(struct kvm_vcpu *vcpu);
> +void kvm_save_lsx(struct loongarch_fpu *fpu);
> +void kvm_restore_lsx(struct loongarch_fpu *fpu);
> +void kvm_restore_lsx_upper(struct loongarch_fpu *fpu);
> +#else
> +static inline void kvm_own_lsx(struct kvm_vcpu *vcpu) { }
> +static inline void kvm_save_lsx(struct loongarch_fpu *fpu) { }
> +static inline void kvm_restore_lsx(struct loongarch_fpu *fpu) { }
> +static inline void kvm_restore_lsx_upper(struct loongarch_fpu *fpu) { }
> +#endif
> +
>   void kvm_acquire_timer(struct kvm_vcpu *vcpu);
>   void kvm_init_timer(struct kvm_vcpu *vcpu, unsigned long hz);
>   void kvm_reset_timer(struct kvm_vcpu *vcpu);
> diff --git a/arch/loongarch/kvm/exit.c b/arch/loongarch/kvm/exit.c
> index ce8de3fa47..1b1c58ccc8 100644
> --- a/arch/loongarch/kvm/exit.c
> +++ b/arch/loongarch/kvm/exit.c
> @@ -659,6 +659,23 @@ static int kvm_handle_fpu_disabled(struct kvm_vcpu *vcpu)
>   	return RESUME_GUEST;
>   }
>   
> +/*
> + * kvm_handle_lsx_disabled() - Guest used LSX while disabled in root.
> + * @vcpu:      Virtual CPU context.
> + *
> + * Handle when the guest attempts to use LSX when it is disabled in the root
> + * context.
> + */
> +static int kvm_handle_lsx_disabled(struct kvm_vcpu *vcpu)
> +{
> +	if (!kvm_guest_has_lsx(&vcpu->arch))
> +		kvm_queue_exception(vcpu, EXCCODE_INE, 0);
> +	else
> +		kvm_own_lsx(vcpu);
> +
> +	return RESUME_GUEST;
> +}
> +
>   /*
>    * LoongArch KVM callback handling for unimplemented guest exiting
>    */
> @@ -687,6 +704,7 @@ static exit_handle_fn kvm_fault_tables[EXCCODE_INT_START] = {
>   	[EXCCODE_TLBS]			= kvm_handle_write_fault,
>   	[EXCCODE_TLBM]			= kvm_handle_write_fault,
>   	[EXCCODE_FPDIS]			= kvm_handle_fpu_disabled,
> +	[EXCCODE_LSXDIS]                = kvm_handle_lsx_disabled,
>   	[EXCCODE_GSPR]			= kvm_handle_gspr,
>   };
>   
> diff --git a/arch/loongarch/kvm/switch.S b/arch/loongarch/kvm/switch.S
> index 0ed9040307..32ba092a44 100644
> --- a/arch/loongarch/kvm/switch.S
> +++ b/arch/loongarch/kvm/switch.S
> @@ -245,6 +245,28 @@ SYM_FUNC_START(kvm_restore_fpu)
>   	jr                 ra
>   SYM_FUNC_END(kvm_restore_fpu)
>   
> +#ifdef CONFIG_CPU_HAS_LSX
> +SYM_FUNC_START(kvm_save_lsx)
> +	fpu_save_csr    a0 t1
> +	fpu_save_cc     a0 t1 t2
> +	lsx_save_data   a0 t1
> +	jirl            zero, ra, 0
> +SYM_FUNC_END(kvm_save_lsx)
> +
> +SYM_FUNC_START(kvm_restore_lsx)
> +	lsx_restore_data a0 t1
> +	fpu_restore_cc   a0 t1 t2
> +	fpu_restore_csr  a0 t1
> +	jirl             zero, ra, 0
> +SYM_FUNC_END(kvm_restore_lsx)
> +
> +SYM_FUNC_START(kvm_restore_lsx_upper)
> +	lsx_restore_all_upper a0 t0 t1
> +
> +	jirl                  zero, ra, 0
> +SYM_FUNC_END(kvm_restore_lsx_upper)
> +#endif
> +
>   	.section ".rodata"
>   SYM_DATA(kvm_exception_size, .quad kvm_exc_entry_end - kvm_exc_entry)
>   SYM_DATA(kvm_enter_guest_size, .quad kvm_enter_guest_end - kvm_enter_guest)
> diff --git a/arch/loongarch/kvm/trace.h b/arch/loongarch/kvm/trace.h
> index a1e35d6554..7da4e230e8 100644
> --- a/arch/loongarch/kvm/trace.h
> +++ b/arch/loongarch/kvm/trace.h
> @@ -102,6 +102,7 @@ TRACE_EVENT(kvm_exit_gspr,
>   #define KVM_TRACE_AUX_DISCARD		4
>   
>   #define KVM_TRACE_AUX_FPU		1
> +#define KVM_TRACE_AUX_LSX		2
>   
>   #define kvm_trace_symbol_aux_op				\
>   	{ KVM_TRACE_AUX_SAVE,		"save" },	\
> @@ -111,7 +112,8 @@ TRACE_EVENT(kvm_exit_gspr,
>   	{ KVM_TRACE_AUX_DISCARD,	"discard" }
>   
>   #define kvm_trace_symbol_aux_state			\
> -	{ KVM_TRACE_AUX_FPU,     "FPU" }
> +	{ KVM_TRACE_AUX_FPU,     "FPU" },		\
> +	{ KVM_TRACE_AUX_LSX,     "LSX" }
>   
>   TRACE_EVENT(kvm_aux,
>   	    TP_PROTO(struct kvm_vcpu *vcpu, unsigned int op,
> diff --git a/arch/loongarch/kvm/vcpu.c b/arch/loongarch/kvm/vcpu.c
> index 73d0c2b9c1..f0bb583353 100644
> --- a/arch/loongarch/kvm/vcpu.c
> +++ b/arch/loongarch/kvm/vcpu.c
> @@ -378,9 +378,13 @@ static int kvm_set_one_reg(struct kvm_vcpu *vcpu,
>   		break;
>   	case KVM_REG_LOONGARCH_CPUCFG:
>   		id = KVM_GET_IOC_CPUCFG_IDX(reg->id);
> -		if (id >= 0 && id < KVM_MAX_CPUCFG_REGS)
> +		if (id >= 0 && id < KVM_MAX_CPUCFG_REGS) {
>   			vcpu->arch.cpucfg[id] = (u32)v;
> -		else
> +			if (id == 2 && v & CPUCFG2_LSX && !cpu_has_lsx) {
Hi Tianrui,

Can you add some annotations about these piece of codes? so that
people can understand easily.

And do we need interface to get host capabilities to user application?
Such as QEMU first gets supported capabilities from kvm and then sets 
the required ones.

Regards
Bibo Mao
> +				vcpu->arch.cpucfg[id] &= ~CPUCFG2_LSX;
> +				ret = -EINVAL;
> +			}
> +		} else
>   			ret = -EINVAL;
>   		break;
>   	case KVM_REG_LOONGARCH_KVM:
> @@ -561,12 +565,49 @@ void kvm_own_fpu(struct kvm_vcpu *vcpu)
>   	preempt_enable();
>   }
>   
> +#ifdef CONFIG_CPU_HAS_LSX
> +/* Enable LSX for guest and restore context */
> +void kvm_own_lsx(struct kvm_vcpu *vcpu)
> +{
> +	preempt_disable();
> +
> +	/* Enable LSX for guest */
> +	set_csr_euen(CSR_EUEN_LSXEN | CSR_EUEN_FPEN);
> +	switch (vcpu->arch.aux_inuse & KVM_LARCH_FPU) {
> +	case KVM_LARCH_FPU:
> +		/*
> +		 * Guest FPU state already loaded,
> +		 * only restore upper LSX state
> +		 */
> +		kvm_restore_lsx_upper(&vcpu->arch.fpu);
> +		break;
> +	default:
> +		/* Neither FP or LSX already active,
> +		 * restore full LSX state
> +		 */
> +		kvm_restore_lsx(&vcpu->arch.fpu);
> +	break;
> +	}
> +
> +	trace_kvm_aux(vcpu, KVM_TRACE_AUX_RESTORE, KVM_TRACE_AUX_LSX);
> +	vcpu->arch.aux_inuse |= KVM_LARCH_LSX | KVM_LARCH_FPU;
> +	preempt_enable();
> +}
> +#endif
> +
>   /* Save context and disable FPU */
>   void kvm_lose_fpu(struct kvm_vcpu *vcpu)
>   {
>   	preempt_disable();
>   
> -	if (vcpu->arch.aux_inuse & KVM_LARCH_FPU) {
> +	if (vcpu->arch.aux_inuse & KVM_LARCH_LSX) {
> +		kvm_save_lsx(&vcpu->arch.fpu);
> +		vcpu->arch.aux_inuse &= ~(KVM_LARCH_LSX | KVM_LARCH_FPU);
> +		trace_kvm_aux(vcpu, KVM_TRACE_AUX_SAVE, KVM_TRACE_AUX_LSX);
> +
> +		/* Disable LSX & FPU */
> +		clear_csr_euen(CSR_EUEN_FPEN | CSR_EUEN_LSXEN);
> +	} else if (vcpu->arch.aux_inuse & KVM_LARCH_FPU) {
>   		kvm_save_fpu(&vcpu->arch.fpu);
>   		vcpu->arch.aux_inuse &= ~KVM_LARCH_FPU;
>   		trace_kvm_aux(vcpu, KVM_TRACE_AUX_SAVE, KVM_TRACE_AUX_FPU);
>
zhaotianrui Nov. 20, 2023, 1:31 a.m. UTC | #4 
在 2023/11/17 下午4:24, maobibo 写道:
>
>
> On 2023/11/15 下午5:19, Tianrui Zhao wrote:
>> This patch adds LSX support for LoongArch KVM. The LSX means
>> LoongArch 128-bits vector instruction.
>> There will be LSX exception in KVM when guest use the LSX
>> instruction. KVM will enable LSX and restore the vector
>> registers for guest then return to guest to continue running.
>>
>>
>> Signed-off-by: Tianrui Zhao <zhaotianrui@loongson.cn>
>> ---
>>   arch/loongarch/include/asm/kvm_host.h |  6 ++++
>>   arch/loongarch/include/asm/kvm_vcpu.h | 12 +++++++
>>   arch/loongarch/kvm/exit.c             | 18 ++++++++++
>>   arch/loongarch/kvm/switch.S           | 22 +++++++++++++
>>   arch/loongarch/kvm/trace.h            |  4 ++-
>>   arch/loongarch/kvm/vcpu.c             | 47 +++++++++++++++++++++++++--
>>   6 files changed, 105 insertions(+), 4 deletions(-)
>>
>> diff --git a/arch/loongarch/include/asm/kvm_host.h 
>> b/arch/loongarch/include/asm/kvm_host.h
>> index 11328700d4..6c65c25169 100644
>> --- a/arch/loongarch/include/asm/kvm_host.h
>> +++ b/arch/loongarch/include/asm/kvm_host.h
>> @@ -94,6 +94,7 @@ enum emulation_result {
>>   #define KVM_LARCH_FPU        (0x1 << 0)
>>   #define KVM_LARCH_SWCSR_LATEST    (0x1 << 1)
>>   #define KVM_LARCH_HWCSR_USABLE    (0x1 << 2)
>> +#define KVM_LARCH_LSX        (0x1 << 3)
>>     struct kvm_vcpu_arch {
>>       /*
>> @@ -175,6 +176,11 @@ static inline void writel_sw_gcsr(struct 
>> loongarch_csrs *csr, int reg, unsigned
>>       csr->csrs[reg] = val;
>>   }
>>   +static inline bool kvm_guest_has_lsx(struct kvm_vcpu_arch *arch)
>> +{
>> +    return arch->cpucfg[2] & CPUCFG2_LSX;
>> +}
>> +
>>   /* Debug: dump vcpu state */
>>   int kvm_arch_vcpu_dump_regs(struct kvm_vcpu *vcpu);
>>   diff --git a/arch/loongarch/include/asm/kvm_vcpu.h 
>> b/arch/loongarch/include/asm/kvm_vcpu.h
>> index 553cfa2b2b..c629771e12 100644
>> --- a/arch/loongarch/include/asm/kvm_vcpu.h
>> +++ b/arch/loongarch/include/asm/kvm_vcpu.h
>> @@ -55,6 +55,18 @@ void kvm_save_fpu(struct loongarch_fpu *fpu);
>>   void kvm_restore_fpu(struct loongarch_fpu *fpu);
>>   void kvm_restore_fcsr(struct loongarch_fpu *fpu);
>>   +#ifdef CONFIG_CPU_HAS_LSX
>> +void kvm_own_lsx(struct kvm_vcpu *vcpu);
>> +void kvm_save_lsx(struct loongarch_fpu *fpu);
>> +void kvm_restore_lsx(struct loongarch_fpu *fpu);
>> +void kvm_restore_lsx_upper(struct loongarch_fpu *fpu);
>> +#else
>> +static inline void kvm_own_lsx(struct kvm_vcpu *vcpu) { }
>> +static inline void kvm_save_lsx(struct loongarch_fpu *fpu) { }
>> +static inline void kvm_restore_lsx(struct loongarch_fpu *fpu) { }
>> +static inline void kvm_restore_lsx_upper(struct loongarch_fpu *fpu) { }
>> +#endif
>> +
>>   void kvm_acquire_timer(struct kvm_vcpu *vcpu);
>>   void kvm_init_timer(struct kvm_vcpu *vcpu, unsigned long hz);
>>   void kvm_reset_timer(struct kvm_vcpu *vcpu);
>> diff --git a/arch/loongarch/kvm/exit.c b/arch/loongarch/kvm/exit.c
>> index ce8de3fa47..1b1c58ccc8 100644
>> --- a/arch/loongarch/kvm/exit.c
>> +++ b/arch/loongarch/kvm/exit.c
>> @@ -659,6 +659,23 @@ static int kvm_handle_fpu_disabled(struct 
>> kvm_vcpu *vcpu)
>>       return RESUME_GUEST;
>>   }
>>   +/*
>> + * kvm_handle_lsx_disabled() - Guest used LSX while disabled in root.
>> + * @vcpu:      Virtual CPU context.
>> + *
>> + * Handle when the guest attempts to use LSX when it is disabled in 
>> the root
>> + * context.
>> + */
>> +static int kvm_handle_lsx_disabled(struct kvm_vcpu *vcpu)
>> +{
>> +    if (!kvm_guest_has_lsx(&vcpu->arch))
>> +        kvm_queue_exception(vcpu, EXCCODE_INE, 0);
>> +    else
>> +        kvm_own_lsx(vcpu);
>> +
>> +    return RESUME_GUEST;
>> +}
>> +
>>   /*
>>    * LoongArch KVM callback handling for unimplemented guest exiting
>>    */
>> @@ -687,6 +704,7 @@ static exit_handle_fn 
>> kvm_fault_tables[EXCCODE_INT_START] = {
>>       [EXCCODE_TLBS]            = kvm_handle_write_fault,
>>       [EXCCODE_TLBM]            = kvm_handle_write_fault,
>>       [EXCCODE_FPDIS]            = kvm_handle_fpu_disabled,
>> +    [EXCCODE_LSXDIS]                = kvm_handle_lsx_disabled,
>>       [EXCCODE_GSPR]            = kvm_handle_gspr,
>>   };
>>   diff --git a/arch/loongarch/kvm/switch.S b/arch/loongarch/kvm/switch.S
>> index 0ed9040307..32ba092a44 100644
>> --- a/arch/loongarch/kvm/switch.S
>> +++ b/arch/loongarch/kvm/switch.S
>> @@ -245,6 +245,28 @@ SYM_FUNC_START(kvm_restore_fpu)
>>       jr                 ra
>>   SYM_FUNC_END(kvm_restore_fpu)
>>   +#ifdef CONFIG_CPU_HAS_LSX
>> +SYM_FUNC_START(kvm_save_lsx)
>> +    fpu_save_csr    a0 t1
>> +    fpu_save_cc     a0 t1 t2
>> +    lsx_save_data   a0 t1
>> +    jirl            zero, ra, 0
>> +SYM_FUNC_END(kvm_save_lsx)
>> +
>> +SYM_FUNC_START(kvm_restore_lsx)
>> +    lsx_restore_data a0 t1
>> +    fpu_restore_cc   a0 t1 t2
>> +    fpu_restore_csr  a0 t1
>> +    jirl             zero, ra, 0
>> +SYM_FUNC_END(kvm_restore_lsx)
>> +
>> +SYM_FUNC_START(kvm_restore_lsx_upper)
>> +    lsx_restore_all_upper a0 t0 t1
>> +
>> +    jirl                  zero, ra, 0
>> +SYM_FUNC_END(kvm_restore_lsx_upper)
>> +#endif
>> +
>>       .section ".rodata"
>>   SYM_DATA(kvm_exception_size, .quad kvm_exc_entry_end - kvm_exc_entry)
>>   SYM_DATA(kvm_enter_guest_size, .quad kvm_enter_guest_end - 
>> kvm_enter_guest)
>> diff --git a/arch/loongarch/kvm/trace.h b/arch/loongarch/kvm/trace.h
>> index a1e35d6554..7da4e230e8 100644
>> --- a/arch/loongarch/kvm/trace.h
>> +++ b/arch/loongarch/kvm/trace.h
>> @@ -102,6 +102,7 @@ TRACE_EVENT(kvm_exit_gspr,
>>   #define KVM_TRACE_AUX_DISCARD        4
>>     #define KVM_TRACE_AUX_FPU        1
>> +#define KVM_TRACE_AUX_LSX        2
>>     #define kvm_trace_symbol_aux_op                \
>>       { KVM_TRACE_AUX_SAVE,        "save" },    \
>> @@ -111,7 +112,8 @@ TRACE_EVENT(kvm_exit_gspr,
>>       { KVM_TRACE_AUX_DISCARD,    "discard" }
>>     #define kvm_trace_symbol_aux_state            \
>> -    { KVM_TRACE_AUX_FPU,     "FPU" }
>> +    { KVM_TRACE_AUX_FPU,     "FPU" },        \
>> +    { KVM_TRACE_AUX_LSX,     "LSX" }
>>     TRACE_EVENT(kvm_aux,
>>           TP_PROTO(struct kvm_vcpu *vcpu, unsigned int op,
>> diff --git a/arch/loongarch/kvm/vcpu.c b/arch/loongarch/kvm/vcpu.c
>> index 73d0c2b9c1..f0bb583353 100644
>> --- a/arch/loongarch/kvm/vcpu.c
>> +++ b/arch/loongarch/kvm/vcpu.c
>> @@ -378,9 +378,13 @@ static int kvm_set_one_reg(struct kvm_vcpu *vcpu,
>>           break;
>>       case KVM_REG_LOONGARCH_CPUCFG:
>>           id = KVM_GET_IOC_CPUCFG_IDX(reg->id);
>> -        if (id >= 0 && id < KVM_MAX_CPUCFG_REGS)
>> +        if (id >= 0 && id < KVM_MAX_CPUCFG_REGS) {
>>               vcpu->arch.cpucfg[id] = (u32)v;
>> -        else
>> +            if (id == 2 && v & CPUCFG2_LSX && !cpu_has_lsx) {
> Hi Tianrui,
>
> Can you add some annotations about these piece of codes? so that
> people can understand easily.
>
> And do we need interface to get host capabilities to user application?
> Such as QEMU first gets supported capabilities from kvm and then sets 
> the required ones.
>
> Regards
> Bibo Mao
Thanks, I will add annotations for this and I think it is better to add 
the checking LSX,LASX capabilities interfaces for user space and I will 
supplement it later.

Thanks
Tianrui Zhao
>> +                vcpu->arch.cpucfg[id] &= ~CPUCFG2_LSX;
>> +                ret = -EINVAL;
>> +            }
>> +        } else
>>               ret = -EINVAL;
>>           break;
>>       case KVM_REG_LOONGARCH_KVM:
>> @@ -561,12 +565,49 @@ void kvm_own_fpu(struct kvm_vcpu *vcpu)
>>       preempt_enable();
>>   }
>>   +#ifdef CONFIG_CPU_HAS_LSX
>> +/* Enable LSX for guest and restore context */
>> +void kvm_own_lsx(struct kvm_vcpu *vcpu)
>> +{
>> +    preempt_disable();
>> +
>> +    /* Enable LSX for guest */
>> +    set_csr_euen(CSR_EUEN_LSXEN | CSR_EUEN_FPEN);
>> +    switch (vcpu->arch.aux_inuse & KVM_LARCH_FPU) {
>> +    case KVM_LARCH_FPU:
>> +        /*
>> +         * Guest FPU state already loaded,
>> +         * only restore upper LSX state
>> +         */
>> +        kvm_restore_lsx_upper(&vcpu->arch.fpu);
>> +        break;
>> +    default:
>> +        /* Neither FP or LSX already active,
>> +         * restore full LSX state
>> +         */
>> +        kvm_restore_lsx(&vcpu->arch.fpu);
>> +    break;
>> +    }
>> +
>> +    trace_kvm_aux(vcpu, KVM_TRACE_AUX_RESTORE, KVM_TRACE_AUX_LSX);
>> +    vcpu->arch.aux_inuse |= KVM_LARCH_LSX | KVM_LARCH_FPU;
>> +    preempt_enable();
>> +}
>> +#endif
>> +
>>   /* Save context and disable FPU */
>>   void kvm_lose_fpu(struct kvm_vcpu *vcpu)
>>   {
>>       preempt_disable();
>>   -    if (vcpu->arch.aux_inuse & KVM_LARCH_FPU) {
>> +    if (vcpu->arch.aux_inuse & KVM_LARCH_LSX) {
>> +        kvm_save_lsx(&vcpu->arch.fpu);
>> +        vcpu->arch.aux_inuse &= ~(KVM_LARCH_LSX | KVM_LARCH_FPU);
>> +        trace_kvm_aux(vcpu, KVM_TRACE_AUX_SAVE, KVM_TRACE_AUX_LSX);
>> +
>> +        /* Disable LSX & FPU */
>> +        clear_csr_euen(CSR_EUEN_FPEN | CSR_EUEN_LSXEN);
>> +    } else if (vcpu->arch.aux_inuse & KVM_LARCH_FPU) {
>>           kvm_save_fpu(&vcpu->arch.fpu);
>>           vcpu->arch.aux_inuse &= ~KVM_LARCH_FPU;
>>           trace_kvm_aux(vcpu, KVM_TRACE_AUX_SAVE, KVM_TRACE_AUX_FPU);
>>
zhaotianrui Nov. 21, 2023, 9:56 a.m. UTC | #5 
在 2023/11/16 下午3:15, WANG Xuerui 写道:
>
> On 11/15/23 17:19, Tianrui Zhao wrote:
>> This patch adds LSX support for LoongArch KVM. The LSX means
>> LoongArch 128-bits vector instruction.
> Maybe we don't need to explain what "LSX" is; people working on 
> LoongArch kernel should already know this through the kernel docs and 
> the various occurrences in the code.
Thanks, I will remove the explain about "LSX, LASX".
>> There will be LSX exception in KVM when guest use the LSX
>> instruction. KVM will enable LSX and restore the vector
>> registers for guest then return to guest to continue running.
>>
> One more extra line that should get removed.
Thanks, I will remove the extra line.
>> Signed-off-by: Tianrui Zhao <zhaotianrui@loongson.cn>
>> ---
>>   arch/loongarch/include/asm/kvm_host.h |  6 ++++
>>   arch/loongarch/include/asm/kvm_vcpu.h | 12 +++++++
>>   arch/loongarch/kvm/exit.c             | 18 ++++++++++
>>   arch/loongarch/kvm/switch.S           | 22 +++++++++++++
>>   arch/loongarch/kvm/trace.h            |  4 ++-
>>   arch/loongarch/kvm/vcpu.c             | 47 +++++++++++++++++++++++++--
>>   6 files changed, 105 insertions(+), 4 deletions(-)
>>
>> diff --git a/arch/loongarch/include/asm/kvm_host.h 
>> b/arch/loongarch/include/asm/kvm_host.h
>> index 11328700d4..6c65c25169 100644
>> --- a/arch/loongarch/include/asm/kvm_host.h
>> +++ b/arch/loongarch/include/asm/kvm_host.h
>> @@ -94,6 +94,7 @@ enum emulation_result {
>>   #define KVM_LARCH_FPU        (0x1 << 0)
>>   #define KVM_LARCH_SWCSR_LATEST    (0x1 << 1)
>>   #define KVM_LARCH_HWCSR_USABLE    (0x1 << 2)
>> +#define KVM_LARCH_LSX        (0x1 << 3)
>>     struct kvm_vcpu_arch {
>>       /*
>> @@ -175,6 +176,11 @@ static inline void writel_sw_gcsr(struct 
>> loongarch_csrs *csr, int reg, unsigned
>>       csr->csrs[reg] = val;
>>   }
>>   +static inline bool kvm_guest_has_lsx(struct kvm_vcpu_arch *arch)
>> +{
>> +    return arch->cpucfg[2] & CPUCFG2_LSX;
>> +}
>> +
>>   /* Debug: dump vcpu state */
>>   int kvm_arch_vcpu_dump_regs(struct kvm_vcpu *vcpu);
>>   diff --git a/arch/loongarch/include/asm/kvm_vcpu.h 
>> b/arch/loongarch/include/asm/kvm_vcpu.h
>> index 553cfa2b2b..c629771e12 100644
>> --- a/arch/loongarch/include/asm/kvm_vcpu.h
>> +++ b/arch/loongarch/include/asm/kvm_vcpu.h
>> @@ -55,6 +55,18 @@ void kvm_save_fpu(struct loongarch_fpu *fpu);
>>   void kvm_restore_fpu(struct loongarch_fpu *fpu);
>>   void kvm_restore_fcsr(struct loongarch_fpu *fpu);
>>   +#ifdef CONFIG_CPU_HAS_LSX
>> +void kvm_own_lsx(struct kvm_vcpu *vcpu);
>> +void kvm_save_lsx(struct loongarch_fpu *fpu);
>> +void kvm_restore_lsx(struct loongarch_fpu *fpu);
>> +void kvm_restore_lsx_upper(struct loongarch_fpu *fpu);
>> +#else
>> +static inline void kvm_own_lsx(struct kvm_vcpu *vcpu) { }
>> +static inline void kvm_save_lsx(struct loongarch_fpu *fpu) { }
>> +static inline void kvm_restore_lsx(struct loongarch_fpu *fpu) { }
>> +static inline void kvm_restore_lsx_upper(struct loongarch_fpu *fpu) { }
>> +#endif
>> +
>>   void kvm_acquire_timer(struct kvm_vcpu *vcpu);
>>   void kvm_init_timer(struct kvm_vcpu *vcpu, unsigned long hz);
>>   void kvm_reset_timer(struct kvm_vcpu *vcpu);
>> diff --git a/arch/loongarch/kvm/exit.c b/arch/loongarch/kvm/exit.c
>> index ce8de3fa47..1b1c58ccc8 100644
>> --- a/arch/loongarch/kvm/exit.c
>> +++ b/arch/loongarch/kvm/exit.c
>> @@ -659,6 +659,23 @@ static int kvm_handle_fpu_disabled(struct 
>> kvm_vcpu *vcpu)
>>       return RESUME_GUEST;
>>   }
>>   +/*
>> + * kvm_handle_lsx_disabled() - Guest used LSX while disabled in root.
>> + * @vcpu:      Virtual CPU context.
>> + *
>> + * Handle when the guest attempts to use LSX when it is disabled in 
>> the root
>> + * context.
>> + */
>> +static int kvm_handle_lsx_disabled(struct kvm_vcpu *vcpu)
>> +{
>> +    if (!kvm_guest_has_lsx(&vcpu->arch))
>> +        kvm_queue_exception(vcpu, EXCCODE_INE, 0);
>> +    else
>> +        kvm_own_lsx(vcpu);
>> +
>> +    return RESUME_GUEST;
>> +}
>> +
>>   /*
>>    * LoongArch KVM callback handling for unimplemented guest exiting
>>    */
>> @@ -687,6 +704,7 @@ static exit_handle_fn 
>> kvm_fault_tables[EXCCODE_INT_START] = {
>>       [EXCCODE_TLBS]            = kvm_handle_write_fault,
>>       [EXCCODE_TLBM]            = kvm_handle_write_fault,
>>       [EXCCODE_FPDIS]            = kvm_handle_fpu_disabled,
>> +    [EXCCODE_LSXDIS]                = kvm_handle_lsx_disabled,
>>       [EXCCODE_GSPR]            = kvm_handle_gspr,
>>   };
>>   diff --git a/arch/loongarch/kvm/switch.S b/arch/loongarch/kvm/switch.S
>> index 0ed9040307..32ba092a44 100644
>> --- a/arch/loongarch/kvm/switch.S
>> +++ b/arch/loongarch/kvm/switch.S
>> @@ -245,6 +245,28 @@ SYM_FUNC_START(kvm_restore_fpu)
>>       jr                 ra
>>   SYM_FUNC_END(kvm_restore_fpu)
>>   +#ifdef CONFIG_CPU_HAS_LSX
>> +SYM_FUNC_START(kvm_save_lsx)
>> +    fpu_save_csr    a0 t1
>> +    fpu_save_cc     a0 t1 t2
>> +    lsx_save_data   a0 t1
>> +    jirl            zero, ra, 0
> "jr ra" for consistency (e.g. with the function immediately above); 
> similarly for other such usages.
Thanks, I will use "jr ra" there.

Tianrui Zhao
>> +SYM_FUNC_END(kvm_save_lsx)
>> +
>> +SYM_FUNC_START(kvm_restore_lsx)
>> +    lsx_restore_data a0 t1
>> +    fpu_restore_cc   a0 t1 t2
>> +    fpu_restore_csr  a0 t1
>> +    jirl             zero, ra, 0
>> +SYM_FUNC_END(kvm_restore_lsx)
>> +
>> +SYM_FUNC_START(kvm_restore_lsx_upper)
>> +    lsx_restore_all_upper a0 t0 t1
>> +
>> +    jirl                  zero, ra, 0
>> +SYM_FUNC_END(kvm_restore_lsx_upper)
>> +#endif
>> +
>>       .section ".rodata"
>>   SYM_DATA(kvm_exception_size, .quad kvm_exc_entry_end - kvm_exc_entry)
>>   SYM_DATA(kvm_enter_guest_size, .quad kvm_enter_guest_end - 
>> kvm_enter_guest)
>> diff --git a/arch/loongarch/kvm/trace.h b/arch/loongarch/kvm/trace.h
>> index a1e35d6554..7da4e230e8 100644
>> --- a/arch/loongarch/kvm/trace.h
>> +++ b/arch/loongarch/kvm/trace.h
>> @@ -102,6 +102,7 @@ TRACE_EVENT(kvm_exit_gspr,
>>   #define KVM_TRACE_AUX_DISCARD        4
>>     #define KVM_TRACE_AUX_FPU        1
>> +#define KVM_TRACE_AUX_LSX        2
>>     #define kvm_trace_symbol_aux_op                \
>>       { KVM_TRACE_AUX_SAVE,        "save" },    \
>> @@ -111,7 +112,8 @@ TRACE_EVENT(kvm_exit_gspr,
>>       { KVM_TRACE_AUX_DISCARD,    "discard" }
>>     #define kvm_trace_symbol_aux_state            \
>> -    { KVM_TRACE_AUX_FPU,     "FPU" }
>> +    { KVM_TRACE_AUX_FPU,     "FPU" },        \
>> +    { KVM_TRACE_AUX_LSX,     "LSX" }
>>     TRACE_EVENT(kvm_aux,
>>           TP_PROTO(struct kvm_vcpu *vcpu, unsigned int op,
>> diff --git a/arch/loongarch/kvm/vcpu.c b/arch/loongarch/kvm/vcpu.c
>> index 73d0c2b9c1..f0bb583353 100644
>> --- a/arch/loongarch/kvm/vcpu.c
>> +++ b/arch/loongarch/kvm/vcpu.c
>> @@ -378,9 +378,13 @@ static int kvm_set_one_reg(struct kvm_vcpu *vcpu,
>>           break;
>>       case KVM_REG_LOONGARCH_CPUCFG:
>>           id = KVM_GET_IOC_CPUCFG_IDX(reg->id);
>> -        if (id >= 0 && id < KVM_MAX_CPUCFG_REGS)
>> +        if (id >= 0 && id < KVM_MAX_CPUCFG_REGS) {
>>               vcpu->arch.cpucfg[id] = (u32)v;
>> -        else
>> +            if (id == 2 && v & CPUCFG2_LSX && !cpu_has_lsx) {
>> +                vcpu->arch.cpucfg[id] &= ~CPUCFG2_LSX;
>> +                ret = -EINVAL;
>> +            }
>> +        } else
>>               ret = -EINVAL;
>>           break;
>>       case KVM_REG_LOONGARCH_KVM:
>> @@ -561,12 +565,49 @@ void kvm_own_fpu(struct kvm_vcpu *vcpu)
>>       preempt_enable();
>>   }
>>   +#ifdef CONFIG_CPU_HAS_LSX
>> +/* Enable LSX for guest and restore context */
>> +void kvm_own_lsx(struct kvm_vcpu *vcpu)
>> +{
>> +    preempt_disable();
>> +
>> +    /* Enable LSX for guest */
>> +    set_csr_euen(CSR_EUEN_LSXEN | CSR_EUEN_FPEN);
>> +    switch (vcpu->arch.aux_inuse & KVM_LARCH_FPU) {
>> +    case KVM_LARCH_FPU:
>> +        /*
>> +         * Guest FPU state already loaded,
>> +         * only restore upper LSX state
>> +         */
>> +        kvm_restore_lsx_upper(&vcpu->arch.fpu);
>> +        break;
>> +    default:
>> +        /* Neither FP or LSX already active,
>> +         * restore full LSX state
>> +         */
>> +        kvm_restore_lsx(&vcpu->arch.fpu);
>> +    break;
>> +    }
>> +
>> +    trace_kvm_aux(vcpu, KVM_TRACE_AUX_RESTORE, KVM_TRACE_AUX_LSX);
>> +    vcpu->arch.aux_inuse |= KVM_LARCH_LSX | KVM_LARCH_FPU;
>> +    preempt_enable();
>> +}
>> +#endif
>> +
>>   /* Save context and disable FPU */
>>   void kvm_lose_fpu(struct kvm_vcpu *vcpu)
>>   {
>>       preempt_disable();
>>   -    if (vcpu->arch.aux_inuse & KVM_LARCH_FPU) {
>> +    if (vcpu->arch.aux_inuse & KVM_LARCH_LSX) {
>> +        kvm_save_lsx(&vcpu->arch.fpu);
>> +        vcpu->arch.aux_inuse &= ~(KVM_LARCH_LSX | KVM_LARCH_FPU);
>> +        trace_kvm_aux(vcpu, KVM_TRACE_AUX_SAVE, KVM_TRACE_AUX_LSX);
>> +
>> +        /* Disable LSX & FPU */
>> +        clear_csr_euen(CSR_EUEN_FPEN | CSR_EUEN_LSXEN);
>> +    } else if (vcpu->arch.aux_inuse & KVM_LARCH_FPU) {
>>           kvm_save_fpu(&vcpu->arch.fpu);
>>           vcpu->arch.aux_inuse &= ~KVM_LARCH_FPU;
>>           trace_kvm_aux(vcpu, KVM_TRACE_AUX_SAVE, KVM_TRACE_AUX_FPU);
>
diff mbox series

Patch

diff --git a/arch/loongarch/include/asm/kvm_host.h b/arch/loongarch/include/asm/kvm_host.h
index 11328700d4..6c65c25169 100644
--- a/arch/loongarch/include/asm/kvm_host.h
+++ b/arch/loongarch/include/asm/kvm_host.h
@@ -94,6 +94,7 @@  enum emulation_result {
 #define KVM_LARCH_FPU		(0x1 << 0)
 #define KVM_LARCH_SWCSR_LATEST	(0x1 << 1)
 #define KVM_LARCH_HWCSR_USABLE	(0x1 << 2)
+#define KVM_LARCH_LSX		(0x1 << 3)
 
 struct kvm_vcpu_arch {
 	/*
@@ -175,6 +176,11 @@  static inline void writel_sw_gcsr(struct loongarch_csrs *csr, int reg, unsigned
 	csr->csrs[reg] = val;
 }
 
+static inline bool kvm_guest_has_lsx(struct kvm_vcpu_arch *arch)
+{
+	return arch->cpucfg[2] & CPUCFG2_LSX;
+}
+
 /* Debug: dump vcpu state */
 int kvm_arch_vcpu_dump_regs(struct kvm_vcpu *vcpu);
 
diff --git a/arch/loongarch/include/asm/kvm_vcpu.h b/arch/loongarch/include/asm/kvm_vcpu.h
index 553cfa2b2b..c629771e12 100644
--- a/arch/loongarch/include/asm/kvm_vcpu.h
+++ b/arch/loongarch/include/asm/kvm_vcpu.h
@@ -55,6 +55,18 @@  void kvm_save_fpu(struct loongarch_fpu *fpu);
 void kvm_restore_fpu(struct loongarch_fpu *fpu);
 void kvm_restore_fcsr(struct loongarch_fpu *fpu);
 
+#ifdef CONFIG_CPU_HAS_LSX
+void kvm_own_lsx(struct kvm_vcpu *vcpu);
+void kvm_save_lsx(struct loongarch_fpu *fpu);
+void kvm_restore_lsx(struct loongarch_fpu *fpu);
+void kvm_restore_lsx_upper(struct loongarch_fpu *fpu);
+#else
+static inline void kvm_own_lsx(struct kvm_vcpu *vcpu) { }
+static inline void kvm_save_lsx(struct loongarch_fpu *fpu) { }
+static inline void kvm_restore_lsx(struct loongarch_fpu *fpu) { }
+static inline void kvm_restore_lsx_upper(struct loongarch_fpu *fpu) { }
+#endif
+
 void kvm_acquire_timer(struct kvm_vcpu *vcpu);
 void kvm_init_timer(struct kvm_vcpu *vcpu, unsigned long hz);
 void kvm_reset_timer(struct kvm_vcpu *vcpu);
diff --git a/arch/loongarch/kvm/exit.c b/arch/loongarch/kvm/exit.c
index ce8de3fa47..1b1c58ccc8 100644
--- a/arch/loongarch/kvm/exit.c
+++ b/arch/loongarch/kvm/exit.c
@@ -659,6 +659,23 @@  static int kvm_handle_fpu_disabled(struct kvm_vcpu *vcpu)
 	return RESUME_GUEST;
 }
 
+/*
+ * kvm_handle_lsx_disabled() - Guest used LSX while disabled in root.
+ * @vcpu:      Virtual CPU context.
+ *
+ * Handle when the guest attempts to use LSX when it is disabled in the root
+ * context.
+ */
+static int kvm_handle_lsx_disabled(struct kvm_vcpu *vcpu)
+{
+	if (!kvm_guest_has_lsx(&vcpu->arch))
+		kvm_queue_exception(vcpu, EXCCODE_INE, 0);
+	else
+		kvm_own_lsx(vcpu);
+
+	return RESUME_GUEST;
+}
+
 /*
  * LoongArch KVM callback handling for unimplemented guest exiting
  */
@@ -687,6 +704,7 @@  static exit_handle_fn kvm_fault_tables[EXCCODE_INT_START] = {
 	[EXCCODE_TLBS]			= kvm_handle_write_fault,
 	[EXCCODE_TLBM]			= kvm_handle_write_fault,
 	[EXCCODE_FPDIS]			= kvm_handle_fpu_disabled,
+	[EXCCODE_LSXDIS]                = kvm_handle_lsx_disabled,
 	[EXCCODE_GSPR]			= kvm_handle_gspr,
 };
 
diff --git a/arch/loongarch/kvm/switch.S b/arch/loongarch/kvm/switch.S
index 0ed9040307..32ba092a44 100644
--- a/arch/loongarch/kvm/switch.S
+++ b/arch/loongarch/kvm/switch.S
@@ -245,6 +245,28 @@  SYM_FUNC_START(kvm_restore_fpu)
 	jr                 ra
 SYM_FUNC_END(kvm_restore_fpu)
 
+#ifdef CONFIG_CPU_HAS_LSX
+SYM_FUNC_START(kvm_save_lsx)
+	fpu_save_csr    a0 t1
+	fpu_save_cc     a0 t1 t2
+	lsx_save_data   a0 t1
+	jirl            zero, ra, 0
+SYM_FUNC_END(kvm_save_lsx)
+
+SYM_FUNC_START(kvm_restore_lsx)
+	lsx_restore_data a0 t1
+	fpu_restore_cc   a0 t1 t2
+	fpu_restore_csr  a0 t1
+	jirl             zero, ra, 0
+SYM_FUNC_END(kvm_restore_lsx)
+
+SYM_FUNC_START(kvm_restore_lsx_upper)
+	lsx_restore_all_upper a0 t0 t1
+
+	jirl                  zero, ra, 0
+SYM_FUNC_END(kvm_restore_lsx_upper)
+#endif
+
 	.section ".rodata"
 SYM_DATA(kvm_exception_size, .quad kvm_exc_entry_end - kvm_exc_entry)
 SYM_DATA(kvm_enter_guest_size, .quad kvm_enter_guest_end - kvm_enter_guest)
diff --git a/arch/loongarch/kvm/trace.h b/arch/loongarch/kvm/trace.h
index a1e35d6554..7da4e230e8 100644
--- a/arch/loongarch/kvm/trace.h
+++ b/arch/loongarch/kvm/trace.h
@@ -102,6 +102,7 @@  TRACE_EVENT(kvm_exit_gspr,
 #define KVM_TRACE_AUX_DISCARD		4
 
 #define KVM_TRACE_AUX_FPU		1
+#define KVM_TRACE_AUX_LSX		2
 
 #define kvm_trace_symbol_aux_op				\
 	{ KVM_TRACE_AUX_SAVE,		"save" },	\
@@ -111,7 +112,8 @@  TRACE_EVENT(kvm_exit_gspr,
 	{ KVM_TRACE_AUX_DISCARD,	"discard" }
 
 #define kvm_trace_symbol_aux_state			\
-	{ KVM_TRACE_AUX_FPU,     "FPU" }
+	{ KVM_TRACE_AUX_FPU,     "FPU" },		\
+	{ KVM_TRACE_AUX_LSX,     "LSX" }
 
 TRACE_EVENT(kvm_aux,
 	    TP_PROTO(struct kvm_vcpu *vcpu, unsigned int op,
diff --git a/arch/loongarch/kvm/vcpu.c b/arch/loongarch/kvm/vcpu.c
index 73d0c2b9c1..f0bb583353 100644
--- a/arch/loongarch/kvm/vcpu.c
+++ b/arch/loongarch/kvm/vcpu.c
@@ -378,9 +378,13 @@  static int kvm_set_one_reg(struct kvm_vcpu *vcpu,
 		break;
 	case KVM_REG_LOONGARCH_CPUCFG:
 		id = KVM_GET_IOC_CPUCFG_IDX(reg->id);
-		if (id >= 0 && id < KVM_MAX_CPUCFG_REGS)
+		if (id >= 0 && id < KVM_MAX_CPUCFG_REGS) {
 			vcpu->arch.cpucfg[id] = (u32)v;
-		else
+			if (id == 2 && v & CPUCFG2_LSX && !cpu_has_lsx) {
+				vcpu->arch.cpucfg[id] &= ~CPUCFG2_LSX;
+				ret = -EINVAL;
+			}
+		} else
 			ret = -EINVAL;
 		break;
 	case KVM_REG_LOONGARCH_KVM:
@@ -561,12 +565,49 @@  void kvm_own_fpu(struct kvm_vcpu *vcpu)
 	preempt_enable();
 }
 
+#ifdef CONFIG_CPU_HAS_LSX
+/* Enable LSX for guest and restore context */
+void kvm_own_lsx(struct kvm_vcpu *vcpu)
+{
+	preempt_disable();
+
+	/* Enable LSX for guest */
+	set_csr_euen(CSR_EUEN_LSXEN | CSR_EUEN_FPEN);
+	switch (vcpu->arch.aux_inuse & KVM_LARCH_FPU) {
+	case KVM_LARCH_FPU:
+		/*
+		 * Guest FPU state already loaded,
+		 * only restore upper LSX state
+		 */
+		kvm_restore_lsx_upper(&vcpu->arch.fpu);
+		break;
+	default:
+		/* Neither FP or LSX already active,
+		 * restore full LSX state
+		 */
+		kvm_restore_lsx(&vcpu->arch.fpu);
+	break;
+	}
+
+	trace_kvm_aux(vcpu, KVM_TRACE_AUX_RESTORE, KVM_TRACE_AUX_LSX);
+	vcpu->arch.aux_inuse |= KVM_LARCH_LSX | KVM_LARCH_FPU;
+	preempt_enable();
+}
+#endif
+
 /* Save context and disable FPU */
 void kvm_lose_fpu(struct kvm_vcpu *vcpu)
 {
 	preempt_disable();
 
-	if (vcpu->arch.aux_inuse & KVM_LARCH_FPU) {
+	if (vcpu->arch.aux_inuse & KVM_LARCH_LSX) {
+		kvm_save_lsx(&vcpu->arch.fpu);
+		vcpu->arch.aux_inuse &= ~(KVM_LARCH_LSX | KVM_LARCH_FPU);
+		trace_kvm_aux(vcpu, KVM_TRACE_AUX_SAVE, KVM_TRACE_AUX_LSX);
+
+		/* Disable LSX & FPU */
+		clear_csr_euen(CSR_EUEN_FPEN | CSR_EUEN_LSXEN);
+	} else if (vcpu->arch.aux_inuse & KVM_LARCH_FPU) {
 		kvm_save_fpu(&vcpu->arch.fpu);
 		vcpu->arch.aux_inuse &= ~KVM_LARCH_FPU;
 		trace_kvm_aux(vcpu, KVM_TRACE_AUX_SAVE, KVM_TRACE_AUX_FPU);