target/i386/kvm.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-)
From: Tom Lendacky <thomas.lendacky@amd.com>
Currently, the nested state format is hardcoded to VMX. This will result
in kvm_put_nested_state() returning an error because the KVM SVM support
checks for the nested state to be KVM_STATE_NESTED_FORMAT_SVM. As a
result, kvm_arch_put_registers() errors out early.
Update the setting of the format based on the virtualization feature:
VMX - KVM_STATE_NESTED_FORMAT_VMX
SVM - KVM_STATE_NESTED_FORMAT_SVM
Also, fix the code formatting while at it.
Fixes: b16c0e20c7 ("KVM: add support for AMD nested live migration")
Cc: Eduardo Habkost <ehabkost@redhat.com>
Cc: Richard Henderson <richard.henderson@linaro.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
---
target/i386/kvm.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)
diff --git a/target/i386/kvm.c b/target/i386/kvm.c
index cf46259534..a2934dda02 100644
--- a/target/i386/kvm.c
+++ b/target/i386/kvm.c
@@ -1820,12 +1820,14 @@ int kvm_arch_init_vcpu(CPUState *cs)
env->nested_state = g_malloc0(max_nested_state_len);
env->nested_state->size = max_nested_state_len;
- env->nested_state->format = KVM_STATE_NESTED_FORMAT_VMX;
if (cpu_has_vmx(env)) {
- vmx_hdr = &env->nested_state->hdr.vmx;
- vmx_hdr->vmxon_pa = -1ull;
- vmx_hdr->vmcs12_pa = -1ull;
+ env->nested_state->format = KVM_STATE_NESTED_FORMAT_VMX;
+ vmx_hdr = &env->nested_state->hdr.vmx;
+ vmx_hdr->vmxon_pa = -1ull;
+ vmx_hdr->vmcs12_pa = -1ull;
+ } else {
+ env->nested_state->format = KVM_STATE_NESTED_FORMAT_SVM;
}
}
}
--
2.28.0
On 16/11/20 18:02, Tom Lendacky wrote: > From: Tom Lendacky<thomas.lendacky@amd.com> > > Currently, the nested state format is hardcoded to VMX. This will result > in kvm_put_nested_state() returning an error because the KVM SVM support > checks for the nested state to be KVM_STATE_NESTED_FORMAT_SVM. As a > result, kvm_arch_put_registers() errors out early. > > Update the setting of the format based on the virtualization feature: > VMX - KVM_STATE_NESTED_FORMAT_VMX > SVM - KVM_STATE_NESTED_FORMAT_SVM Looks good, but what are the symptoms of this in practice? Paolo
On 11/16/20 12:09 PM, Paolo Bonzini wrote: > On 16/11/20 18:02, Tom Lendacky wrote: >> From: Tom Lendacky<thomas.lendacky@amd.com> >> >> Currently, the nested state format is hardcoded to VMX. This will result >> in kvm_put_nested_state() returning an error because the KVM SVM support >> checks for the nested state to be KVM_STATE_NESTED_FORMAT_SVM. As a >> result, kvm_arch_put_registers() errors out early. >> >> Update the setting of the format based on the virtualization feature: >> VMX - KVM_STATE_NESTED_FORMAT_VMX >> SVM - KVM_STATE_NESTED_FORMAT_SVM > > Looks good, but what are the symptoms of this in practice? I discovered this while testing my SEV-ES patches. When I specified the '+svm' feature, the new SEV-ES reset address for the APs wasn't getting set because kvm_arch_put_registers() erred out before it could call kvm_getput_regs(). This resulted in the guest crashing when OVMF tried to start the APs. For a non-SEV-ES guest, I'm not sure if other updates could be missed, potentially. Thanks, Tom > > Paolo >
On 16/11/20 19:25, Tom Lendacky wrote: > On 11/16/20 12:09 PM, Paolo Bonzini wrote: >> On 16/11/20 18:02, Tom Lendacky wrote: >>> From: Tom Lendacky<thomas.lendacky@amd.com> >>> >>> Currently, the nested state format is hardcoded to VMX. This will result >>> in kvm_put_nested_state() returning an error because the KVM SVM support >>> checks for the nested state to be KVM_STATE_NESTED_FORMAT_SVM. As a >>> result, kvm_arch_put_registers() errors out early. >>> >>> Update the setting of the format based on the virtualization feature: >>> VMX - KVM_STATE_NESTED_FORMAT_VMX >>> SVM - KVM_STATE_NESTED_FORMAT_SVM >> >> Looks good, but what are the symptoms of this in practice? > > I discovered this while testing my SEV-ES patches. When I specified the > '+svm' feature, the new SEV-ES reset address for the APs wasn't getting > set because kvm_arch_put_registers() erred out before it could call > kvm_getput_regs(). This resulted in the guest crashing when OVMF tried to > start the APs. > > For a non-SEV-ES guest, I'm not sure if other updates could be missed, > potentially. Ok, thanks. It's certainly a potential source of bugs, I've queued the patch. Paolo
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