[PATCH RFC: kvm tsc virtualization 07/20] Basic SVM implementation of RDTSC trapping.

[Zachary Amsden]

Add a dumb version of RDTSC trapping for SVM which just passes
through the hardware counter.

Signed-off-by: Zachary Amsden <zams...@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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