diff mbox series

[v12,45/46] KVM: selftests: hyperv_svm_test: Introduce L2 TLB flush test

Message ID 20221021153521.1216911-46-vkuznets@redhat.com
State New
Headers
Series KVM: x86: hyper-v: Fine-grained TLB flush + L2 TLB flush features |

Commit Message

Vitaly Kuznetsov Oct. 21, 2022, 3:35 p.m. UTC 
  Enable Hyper-V L2 TLB flush and check that Hyper-V TLB flush hypercalls
from L2 don't exit to L1 unless 'TlbLockCount' is set in the Partition
assist page.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
---
 .../selftests/kvm/include/x86_64/svm.h        |  4 ++
 .../selftests/kvm/x86_64/hyperv_svm_test.c    | 61 +++++++++++++++++--
 2 files changed, 60 insertions(+), 5 deletions(-)

Comments

Sean Christopherson Oct. 26, 2022, 10:23 p.m. UTC | #1 
On Fri, Oct 21, 2022, Vitaly Kuznetsov wrote:
> Enable Hyper-V L2 TLB flush and check that Hyper-V TLB flush hypercalls
> from L2 don't exit to L1 unless 'TlbLockCount' is set in the Partition
> assist page.
> 
> Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
> ---
>  .../selftests/kvm/include/x86_64/svm.h        |  4 ++
>  .../selftests/kvm/x86_64/hyperv_svm_test.c    | 61 +++++++++++++++++--
>  2 files changed, 60 insertions(+), 5 deletions(-)
> 
> diff --git a/tools/testing/selftests/kvm/include/x86_64/svm.h b/tools/testing/selftests/kvm/include/x86_64/svm.h
> index 483e6ae12f69..4803e1056055 100644
> --- a/tools/testing/selftests/kvm/include/x86_64/svm.h
> +++ b/tools/testing/selftests/kvm/include/x86_64/svm.h
> @@ -76,6 +76,10 @@ struct hv_vmcb_enlightenments {
>   */
>  #define HV_VMCB_NESTED_ENLIGHTENMENTS (1U << 31)
>  
> +/* Synthetic VM-Exit */
> +#define HV_SVM_EXITCODE_ENL			0xf0000000
> +#define HV_SVM_ENL_EXITCODE_TRAP_AFTER_FLUSH	(1)
> +
>  struct __attribute__ ((__packed__)) vmcb_control_area {
>  	u32 intercept_cr;
>  	u32 intercept_dr;
> diff --git a/tools/testing/selftests/kvm/x86_64/hyperv_svm_test.c b/tools/testing/selftests/kvm/x86_64/hyperv_svm_test.c
> index 1c3fc38b4f15..edb779615a79 100644
> --- a/tools/testing/selftests/kvm/x86_64/hyperv_svm_test.c
> +++ b/tools/testing/selftests/kvm/x86_64/hyperv_svm_test.c
> @@ -25,6 +25,8 @@
>  
>  void l2_guest_code(void)
>  {
> +	u64 unused;
> +
>  	GUEST_SYNC(3);
>  	/* Exit to L1 */
>  	vmmcall();
> @@ -38,11 +40,30 @@ void l2_guest_code(void)
>  
>  	GUEST_SYNC(5);
>  
> +	/* L2 TLB flush tests */
> +	hyperv_hypercall(HVCALL_FLUSH_VIRTUAL_ADDRESS_SPACE |
> +			 HV_HYPERCALL_FAST_BIT, 0x0,
> +			 HV_FLUSH_ALL_VIRTUAL_ADDRESS_SPACES |
> +			 HV_FLUSH_ALL_PROCESSORS);
> +	rdmsr(MSR_FS_BASE);

Why doesn't the SVM test need to clobber GPRs?

> +	/*
> +	 * Note: hypercall status (RAX) is not preserved correctly by L1 after
> +	 * synthetic vmexit, use unchecked version.
> +	 */
> +	__hyperv_hypercall(HVCALL_FLUSH_VIRTUAL_ADDRESS_SPACE |
> +			   HV_HYPERCALL_FAST_BIT, 0x0,
> +			   HV_FLUSH_ALL_VIRTUAL_ADDRESS_SPACES |
> +			   HV_FLUSH_ALL_PROCESSORS, &unused);
> +	/* Make sure we're not issuing Hyper-V TLB flush call again */
> +	__asm__ __volatile__ ("mov $0xdeadbeef, %rcx");

Heh, and a patch to vmmcall() itself "safe"...

> +
>  	/* Done, exit to L1 and never come back.  */
>  	vmmcall();
>  }
diff mbox series

Patch

diff --git a/tools/testing/selftests/kvm/include/x86_64/svm.h b/tools/testing/selftests/kvm/include/x86_64/svm.h
index 483e6ae12f69..4803e1056055 100644
--- a/tools/testing/selftests/kvm/include/x86_64/svm.h
+++ b/tools/testing/selftests/kvm/include/x86_64/svm.h
@@ -76,6 +76,10 @@  struct hv_vmcb_enlightenments {
  */
 #define HV_VMCB_NESTED_ENLIGHTENMENTS (1U << 31)
 
+/* Synthetic VM-Exit */
+#define HV_SVM_EXITCODE_ENL			0xf0000000
+#define HV_SVM_ENL_EXITCODE_TRAP_AFTER_FLUSH	(1)
+
 struct __attribute__ ((__packed__)) vmcb_control_area {
 	u32 intercept_cr;
 	u32 intercept_dr;
diff --git a/tools/testing/selftests/kvm/x86_64/hyperv_svm_test.c b/tools/testing/selftests/kvm/x86_64/hyperv_svm_test.c
index 1c3fc38b4f15..edb779615a79 100644
--- a/tools/testing/selftests/kvm/x86_64/hyperv_svm_test.c
+++ b/tools/testing/selftests/kvm/x86_64/hyperv_svm_test.c
@@ -25,6 +25,8 @@ 
 
 void l2_guest_code(void)
 {
+	u64 unused;
+
 	GUEST_SYNC(3);
 	/* Exit to L1 */
 	vmmcall();
@@ -38,11 +40,30 @@  void l2_guest_code(void)
 
 	GUEST_SYNC(5);
 
+	/* L2 TLB flush tests */
+	hyperv_hypercall(HVCALL_FLUSH_VIRTUAL_ADDRESS_SPACE |
+			 HV_HYPERCALL_FAST_BIT, 0x0,
+			 HV_FLUSH_ALL_VIRTUAL_ADDRESS_SPACES |
+			 HV_FLUSH_ALL_PROCESSORS);
+	rdmsr(MSR_FS_BASE);
+	/*
+	 * Note: hypercall status (RAX) is not preserved correctly by L1 after
+	 * synthetic vmexit, use unchecked version.
+	 */
+	__hyperv_hypercall(HVCALL_FLUSH_VIRTUAL_ADDRESS_SPACE |
+			   HV_HYPERCALL_FAST_BIT, 0x0,
+			   HV_FLUSH_ALL_VIRTUAL_ADDRESS_SPACES |
+			   HV_FLUSH_ALL_PROCESSORS, &unused);
+	/* Make sure we're not issuing Hyper-V TLB flush call again */
+	__asm__ __volatile__ ("mov $0xdeadbeef, %rcx");
+
 	/* Done, exit to L1 and never come back.  */
 	vmmcall();
 }
 
-static void __attribute__((__flatten__)) guest_code(struct svm_test_data *svm)
+static void __attribute__((__flatten__)) guest_code(struct svm_test_data *svm,
+						    struct hyperv_test_pages *hv_pages,
+						    vm_vaddr_t pgs_gpa)
 {
 	unsigned long l2_guest_stack[L2_GUEST_STACK_SIZE];
 	struct vmcb *vmcb = svm->vmcb;
@@ -50,13 +71,23 @@  static void __attribute__((__flatten__)) guest_code(struct svm_test_data *svm)
 
 	GUEST_SYNC(1);
 
-	wrmsr(HV_X64_MSR_GUEST_OS_ID, (u64)0x8100 << 48);
+	wrmsr(HV_X64_MSR_GUEST_OS_ID, HYPERV_LINUX_OS_ID);
+	wrmsr(HV_X64_MSR_HYPERCALL, pgs_gpa);
+	enable_vp_assist(hv_pages->vp_assist_gpa, hv_pages->vp_assist);
 
 	GUEST_ASSERT(svm->vmcb_gpa);
 	/* Prepare for L2 execution. */
 	generic_svm_setup(svm, l2_guest_code,
 			  &l2_guest_stack[L2_GUEST_STACK_SIZE]);
 
+	/* L2 TLB flush setup */
+	hve->partition_assist_page = hv_pages->partition_assist_gpa;
+	hve->hv_enlightenments_control.nested_flush_hypercall = 1;
+	hve->hv_vm_id = 1;
+	hve->hv_vp_id = 1;
+	current_vp_assist->nested_control.features.directhypercall = 1;
+	*(u32 *)(hv_pages->partition_assist) = 0;
+
 	GUEST_SYNC(2);
 	run_guest(vmcb, svm->vmcb_gpa);
 	GUEST_ASSERT(vmcb->control.exit_code == SVM_EXIT_VMMCALL);
@@ -91,6 +122,20 @@  static void __attribute__((__flatten__)) guest_code(struct svm_test_data *svm)
 	GUEST_ASSERT(vmcb->control.exit_code == SVM_EXIT_MSR);
 	vmcb->save.rip += 2; /* rdmsr */
 
+
+	/*
+	 * L2 TLB flush test. First VMCALL should be handled directly by L0,
+	 * no VMCALL exit expected.
+	 */
+	run_guest(vmcb, svm->vmcb_gpa);
+	GUEST_ASSERT(vmcb->control.exit_code == SVM_EXIT_MSR);
+	vmcb->save.rip += 2; /* rdmsr */
+	/* Enable synthetic vmexit */
+	*(u32 *)(hv_pages->partition_assist) = 1;
+	run_guest(vmcb, svm->vmcb_gpa);
+	GUEST_ASSERT(vmcb->control.exit_code == HV_SVM_EXITCODE_ENL);
+	GUEST_ASSERT(vmcb->control.exit_info_1 == HV_SVM_ENL_EXITCODE_TRAP_AFTER_FLUSH);
+
 	run_guest(vmcb, svm->vmcb_gpa);
 	GUEST_ASSERT(vmcb->control.exit_code == SVM_EXIT_VMMCALL);
 	GUEST_SYNC(6);
@@ -100,8 +145,8 @@  static void __attribute__((__flatten__)) guest_code(struct svm_test_data *svm)
 
 int main(int argc, char *argv[])
 {
-	vm_vaddr_t nested_gva = 0;
-
+	vm_vaddr_t nested_gva = 0, hv_pages_gva = 0;
+	vm_vaddr_t hcall_page;
 	struct kvm_vcpu *vcpu;
 	struct kvm_vm *vm;
 	struct kvm_run *run;
@@ -115,7 +160,13 @@  int main(int argc, char *argv[])
 	vcpu_set_hv_cpuid(vcpu);
 	run = vcpu->run;
 	vcpu_alloc_svm(vm, &nested_gva);
-	vcpu_args_set(vcpu, 1, nested_gva);
+	vcpu_alloc_hyperv_test_pages(vm, &hv_pages_gva);
+
+	hcall_page = vm_vaddr_alloc_pages(vm, 1);
+	memset(addr_gva2hva(vm, hcall_page), 0x0,  getpagesize());
+
+	vcpu_args_set(vcpu, 3, nested_gva, hv_pages_gva, addr_gva2gpa(vm, hcall_page));
+	vcpu_set_msr(vcpu, HV_X64_MSR_VP_INDEX, vcpu->id);
 
 	for (stage = 1;; stage++) {
 		vcpu_run(vcpu);