Re: [PATCH v3 0/3] kvm: vmx: enable xsaves for kvm

Wanpeng Li
2014-12-03T00:30:17Z

On Tue, Dec 02, 2014 at 02:00:24PM +0100, Paolo Bonzini wrote:
>
>
>On 02/12/2014 12:14, Wanpeng Li wrote:
>> This patchset is to enable xsaves for kvm part, the patch for
>> qemu part will be sent out later.
>>
>> The patchset is tested on skylake-client.
>>
>> v2 -> v3:
>> * add kvm_get/set for ia32_xss
>> * fix the type XSS_EXIT_BITMAP
>> * load host_xss just once in setup_vmcs_config
>> * add/clear atuo switch ia32_xss msr in kvm_get/clear
>> * add VMX_XSS_EXIT_BITMAP macro
>> * add WARN() in handle_xsaves/xrstors
>> * export xsaves if related vmcs field is set
>>
>> v1 -> v2:
>> * auto switch ia32_xss msr just if this msr is present
>>
>> Wanpeng Li (3):
>> kvm: x86: Intel XSAVES vmx and msr handle
>> kvm: vmx: add kvm_get/set logic to xsaves
>> kvm: x86: Enable Intel XSAVES for guest
>>
>> arch/x86/include/asm/kvm_host.h | 2 ++
>> arch/x86/include/asm/vmx.h | 3 +++
>> arch/x86/include/uapi/asm/vmx.h | 6 ++++-
>> arch/x86/kvm/cpuid.c | 3 ++-
>> arch/x86/kvm/vmx.c | 51 ++++++++++++++++++++++++++++++++++++++++-
>> 5 files changed, 62 insertions(+), 3 deletions(-)
>>
>
>We need to return false from an svm_xsaves_supported function too, and
>we need to prevent setting MSR_IA32_XSS to any non-zero value because
>we do not support getting/setting a guest's Trace Packet Configuration
>State.
>

Agreed, I will fix them in next version.

>I will squash this hunk in, and send a new patch to return zero for
>CPUID(0xd,i).ECX and CPUID(0xd,i).EDX.

Cool, I will test it.

Regards,
Wanpeng Li

>
>diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
>index 66d1e3d0195e..6e3a4486749c 100644
>--- a/arch/x86/kvm/vmx.c
>+++ b/arch/x86/kvm/vmx.c
>@@ -2671,6 +2671,11 @@ static int vmx_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
> case MSR_IA32_XSS:
> if (!vmx_xsaves_supported())
> return 1;
>+ /* The only supported bit as of Skylake is bit 8, but
>+ * it is not supported on KVM.
>+ */
>+ if (data != 0)
>+ return 1;
> vcpu->arch.ia32_xss = data;
> if (vcpu->arch.ia32_xss != host_xss)
> add_atomic_switch_msr(vmx, MSR_IA32_XSS,
>
>Paolo