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 <joerg.roedel@amd.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index bf5799d..c17404a 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -2059,10 +2059,14 @@
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 @@
switch (ecx) {
case MSR_IA32_TSC: {
- u64 tsc;
+ u64 tsc_offset = data - native_read_tsc();
+ u64 g_tsc_offset = 0;
- rdtscll(tsc);
- svm->vmcb->control.tsc_offset = data - tsc;
+ 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;
+
break;
}
case MSR_K6_STAR: