From 20824f30bb0b8ae0a4099895fd4509f54cf2e1e2 Mon Sep 17 00:00:00 2001 From: Joerg Roedel Date: Wed, 16 Sep 2009 15:24:18 +0200 Subject: [PATCH] KVM: SVM: Handle tsc in svm_get_msr/svm_set_msr correctly When running nested we need to touch the l1 guests tsc_offset. Otherwise changes will be lost or a wrong value be read. Cc: stable@kernel.org Signed-off-by: Joerg Roedel Signed-off-by: Marcelo Tosatti --- arch/x86/kvm/svm.c | 23 +++++++++++++++++------ 1 file changed, 17 insertions(+), 6 deletions(-) diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c index bf5799dc4f9f..c17404add91f 100644 --- a/arch/x86/kvm/svm.c +++ b/arch/x86/kvm/svm.c @@ -2059,10 +2059,14 @@ static int svm_get_msr(struct kvm_vcpu *vcpu, unsigned ecx, u64 *data) switch (ecx) { case MSR_IA32_TSC: { - u64 tsc; + u64 tsc_offset; - rdtscll(tsc); - *data = svm->vmcb->control.tsc_offset + tsc; + if (is_nested(svm)) + tsc_offset = svm->nested.hsave->control.tsc_offset; + else + tsc_offset = svm->vmcb->control.tsc_offset; + + *data = tsc_offset + native_read_tsc(); break; } case MSR_K6_STAR: @@ -2148,10 +2152,17 @@ static int svm_set_msr(struct kvm_vcpu *vcpu, unsigned ecx, u64 data) switch (ecx) { case MSR_IA32_TSC: { - u64 tsc; + u64 tsc_offset = data - native_read_tsc(); + u64 g_tsc_offset = 0; + + if (is_nested(svm)) { + g_tsc_offset = svm->vmcb->control.tsc_offset - + svm->nested.hsave->control.tsc_offset; + svm->nested.hsave->control.tsc_offset = tsc_offset; + } + + svm->vmcb->control.tsc_offset = tsc_offset + g_tsc_offset; - rdtscll(tsc); - svm->vmcb->control.tsc_offset = data - tsc; break; } case MSR_K6_STAR: -- GitLab