On Thu, Jul 25, 2019 at 11:12:46AM +0800, Yang Weijiang wrote:
> There're two different places storing Guest CET states, the states
> managed with XSAVES/XRSTORS, as restored/saved
> in previous patch, can be read/write directly from/to the MSRs.
> For those stored in VMCS fields, they're access via vmcs_read/
> vmcs_write.
>
> Signed-off-by: Yang Weijiang <[email protected]>
> ---
> arch/x86/kvm/vmx/vmx.c | 43 ++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 43 insertions(+)
>
> diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
> index 123285177c6b..e5eacd01e984 100644
> --- a/arch/x86/kvm/vmx/vmx.c
> +++ b/arch/x86/kvm/vmx/vmx.c
> @@ -1774,6 +1774,27 @@ static int vmx_get_msr(struct kvm_vcpu *vcpu, struct
> msr_data *msr_info)
> else
> msr_info->data = vmx->pt_desc.guest.addr_a[index / 2];
> break;
> + case MSR_IA32_S_CET:
> + msr_info->data = vmcs_readl(GUEST_S_CET);
> + break;
> + case MSR_IA32_U_CET:
> + rdmsrl(MSR_IA32_U_CET, msr_info->data);
> + break;
> + case MSR_IA32_INT_SSP_TAB:
> + msr_info->data = vmcs_readl(GUEST_INTR_SSP_TABLE);
> + break;
> + case MSR_IA32_PL0_SSP:
> + rdmsrl(MSR_IA32_PL0_SSP, msr_info->data);
> + break;
> + case MSR_IA32_PL1_SSP:
> + rdmsrl(MSR_IA32_PL1_SSP, msr_info->data);
> + break;
> + case MSR_IA32_PL2_SSP:
> + rdmsrl(MSR_IA32_PL2_SSP, msr_info->data);
> + break;
> + case MSR_IA32_PL3_SSP:
> + rdmsrl(MSR_IA32_PL3_SSP, msr_info->data);
> + break;
These all need appropriate checks on guest and host support. The guest
checks won't come into play very often, if ever, for the MSRs that exist
if IBT *or* SHSTK is supported due to passing the MSRs through to the
guest, but I don't think we want this code reliant on the interception
logic. E.g.:
case MSR_IA32_S_CET:
if (!(host_xss & XFEATURE_MASK_CET_KERNEL))
return 1;
if (!msr_info->host_initiated &&
!guest_cpuid_has(vcpu, X86_FEATURE_SHSTK) &&
!guest_cpuid_has(vcpu, X86_FEATURE_IBT))
return 1;
MSR_IA32_U_CET is same as above, s/KERNEL/USER.
case MSR_IA32_INT_SSP_TAB:
if (!(host_xss & (XFEATURE_MASK_CET_KERNEL |
XFEATURE_MASK_CET_USER)))
return 1;
if (!msr_info->host_initiated &&
!guest_cpuid_has(vcpu, X86_FEATURE_SHSTK))
return 1;
MSR_IA32_PL[0-3]_SSP are same as above, but only check the appropriate
KERNEL or USER bit.
Note, the PL[0-2]_SSP MSRs can be collapsed into a single case, e.g.:
case MSR_IA32_PL0_SSP ... MSR_IA32_PL2_SSP:
<error handling code>;
rdmsrl(msr_index, msr_info->data);
break;
Rinse and repeat for vmx_set_msr().
> case MSR_TSC_AUX:
> if (!msr_info->host_initiated &&
> !guest_cpuid_has(vcpu, X86_FEATURE_RDTSCP))
> @@ -2007,6 +2028,28 @@ static int vmx_set_msr(struct kvm_vcpu *vcpu, struct
> msr_data *msr_info)
> else
> vmx->pt_desc.guest.addr_a[index / 2] = data;
> break;
> + case MSR_IA32_S_CET:
> + vmcs_writel(GUEST_S_CET, data);
> + break;
> + case MSR_IA32_U_CET:
> + wrmsrl(MSR_IA32_U_CET, data);
> + break;
> + case MSR_IA32_INT_SSP_TAB:
> + vmcs_writel(GUEST_INTR_SSP_TABLE, data);
> + break;
> + case MSR_IA32_PL0_SSP:
> + wrmsrl(MSR_IA32_PL0_SSP, data);
> + break;
> + case MSR_IA32_PL1_SSP:
> + wrmsrl(MSR_IA32_PL1_SSP, data);
> + break;
> + case MSR_IA32_PL2_SSP:
> + wrmsrl(MSR_IA32_PL2_SSP, data);
> + break;
> + case MSR_IA32_PL3_SSP:
> + wrmsrl(MSR_IA32_PL3_SSP, data);
> + break;
> +
> case MSR_TSC_AUX:
> if (!msr_info->host_initiated &&
> !guest_cpuid_has(vcpu, X86_FEATURE_RDTSCP))
> --
> 2.17.2
>
