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Subject[PATCH RFC: kvm tsc virtualization 07/20] Basic SVM implementation of RDTSC trapping.
Date
Add a dumb version of RDTSC trapping for SVM which just passes
through the hardware counter.

Signed-off-by: Zachary Amsden <zamsden@redhat.com>
---
arch/x86/kvm/emulate.c | 2 +-
arch/x86/kvm/svm.c | 15 +++++++++++++++
2 files changed, 16 insertions(+), 1 deletions(-)
diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index d226dff..76e180f 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -226,7 +226,7 @@ static u32 twobyte_table[256] = {
ModRM | ImplicitOps, ModRM, ModRM | ImplicitOps, ModRM, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0,
/* 0x30 - 0x3F */
- ImplicitOps, 0, ImplicitOps, 0,
+ ImplicitOps, ImplicitOps, ImplicitOps, 0,
ImplicitOps, ImplicitOps, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0,
/* 0x40 - 0x47 */
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 34b700f..16c9048 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -571,6 +571,7 @@ static void init_vmcb(struct vcpu_svm *svm)
control->intercept = (1ULL << INTERCEPT_INTR) |
(1ULL << INTERCEPT_NMI) |
(1ULL << INTERCEPT_SMI) |
+ (1ULL << INTERCEPT_RDTSC) |
(1ULL << INTERCEPT_CPUID) |
(1ULL << INTERCEPT_INVD) |
(1ULL << INTERCEPT_HLT) |
@@ -2029,6 +2030,19 @@ static int task_switch_interception(struct vcpu_svm *svm)
return kvm_task_switch(&svm->vcpu, tss_selector, reason);
}

+static int rdtsc_interception(struct vcpu_svm *svm)
+{
+ u64 tsc;
+
+ rdtscll(tsc);
+ tsc += svm->vmcb->control.tsc_offset;
+ kvm_register_write(&svm->vcpu, VCPU_REGS_RAX, tsc & 0xffffffff);
+ tsc >>= 32;
+ kvm_register_write(&svm->vcpu, VCPU_REGS_RDX, tsc & 0xffffffff);
+ skip_emulated_instruction(&svm->vcpu);
+ return 1;
+}
+
static int cpuid_interception(struct vcpu_svm *svm)
{
svm->next_rip = kvm_rip_read(&svm->vcpu) + 2;
@@ -2326,6 +2340,7 @@ static int (*svm_exit_handlers[])(struct vcpu_svm *svm) = {
[SVM_EXIT_INIT] = nop_on_interception,
[SVM_EXIT_VINTR] = interrupt_window_interception,
/* [SVM_EXIT_CR0_SEL_WRITE] = emulate_on_interception, */
+ [SVM_EXIT_RDTSC] = rdtsc_interception,
[SVM_EXIT_CPUID] = cpuid_interception,
[SVM_EXIT_IRET] = iret_interception,
[SVM_EXIT_INVD] = emulate_on_interception,
--
1.6.5.2


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