Commit Message
Isaku Yamahata
Feb. 26, 2024, 8:26 a.m. UTC
From: Isaku Yamahata <isaku.yamahata@intel.com> On exiting from the guest TD, xsave state is clobbered. Restore xsave state on TD exit. Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com> --- v19: - Add EXPORT_SYMBOL_GPL(host_xcr0) v15 -> v16: - Added CET flag mask Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com> --- arch/x86/kvm/vmx/tdx.c | 19 +++++++++++++++++++ arch/x86/kvm/x86.c | 1 + 2 files changed, 20 insertions(+)
diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c index 9616b1aab6ce..199226c6cf55 100644 --- a/arch/x86/kvm/vmx/tdx.c +++ b/arch/x86/kvm/vmx/tdx.c @@ -2,6 +2,7 @@ #include <linux/cpu.h> #include <linux/mmu_context.h> +#include <asm/fpu/xcr.h> #include <asm/tdx.h> #include "capabilities.h" @@ -534,6 +535,23 @@ void tdx_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event) */ } +static void tdx_restore_host_xsave_state(struct kvm_vcpu *vcpu) +{ + struct kvm_tdx *kvm_tdx = to_kvm_tdx(vcpu->kvm); + + if (static_cpu_has(X86_FEATURE_XSAVE) && + host_xcr0 != (kvm_tdx->xfam & kvm_caps.supported_xcr0)) + xsetbv(XCR_XFEATURE_ENABLED_MASK, host_xcr0); + if (static_cpu_has(X86_FEATURE_XSAVES) && + /* PT can be exposed to TD guest regardless of KVM's XSS support */ + host_xss != (kvm_tdx->xfam & + (kvm_caps.supported_xss | XFEATURE_MASK_PT | TDX_TD_XFAM_CET))) + wrmsrl(MSR_IA32_XSS, host_xss); + if (static_cpu_has(X86_FEATURE_PKU) && + (kvm_tdx->xfam & XFEATURE_MASK_PKRU)) + write_pkru(vcpu->arch.host_pkru); +} + static noinstr void tdx_vcpu_enter_exit(struct vcpu_tdx *tdx) { struct tdx_module_args args; @@ -609,6 +627,7 @@ fastpath_t tdx_vcpu_run(struct kvm_vcpu *vcpu) tdx_vcpu_enter_exit(tdx); + tdx_restore_host_xsave_state(vcpu); tdx->host_state_need_restore = true; vcpu->arch.regs_avail &= ~VMX_REGS_LAZY_LOAD_SET; diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 23ece956c816..b361d948140f 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -315,6 +315,7 @@ const struct kvm_stats_header kvm_vcpu_stats_header = { }; u64 __read_mostly host_xcr0; +EXPORT_SYMBOL_GPL(host_xcr0); static struct kmem_cache *x86_emulator_cache;