* [PATCH] KVM: nVMX: Set X86_CR4_CET in cr4_fixed1_bits if CET IBT is enabled
@ 2021-02-25 3:09 Yang Weijiang
2021-02-25 3:09 ` [PATCH v2] KVM: nVMX: Sync L2 guest CET states between L1/L2 Yang Weijiang
2021-03-01 17:39 ` [PATCH] KVM: nVMX: Set X86_CR4_CET in cr4_fixed1_bits if CET IBT is enabled Sean Christopherson
0 siblings, 2 replies; 8+ messages in thread
From: Yang Weijiang @ 2021-02-25 3:09 UTC (permalink / raw)
To: pbonzini, seanjc, kvm, linux-kernel; +Cc: Yang Weijiang
CET SHSTK and IBT are independently controlled by kernel, set X86_CR4_CET
bit in cr4_fixed1_bits if either of them is enabled so that nested guest
can enjoy the feature.
Signed-off-by: Yang Weijiang <weijiang.yang@intel.com>
---
arch/x86/kvm/vmx/vmx.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 5856c5b81084..e92134ee081c 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -7258,6 +7258,7 @@ static void nested_vmx_cr_fixed1_bits_update(struct kvm_vcpu *vcpu)
cr4_fixed1_update(X86_CR4_UMIP, ecx, feature_bit(UMIP));
cr4_fixed1_update(X86_CR4_LA57, ecx, feature_bit(LA57));
cr4_fixed1_update(X86_CR4_CET, ecx, feature_bit(SHSTK));
+ cr4_fixed1_update(X86_CR4_CET, edx, feature_bit(IBT));
#undef cr4_fixed1_update
}
--
2.26.2
^ permalink raw reply related [flat|nested] 8+ messages in thread
* [PATCH v2] KVM: nVMX: Sync L2 guest CET states between L1/L2
2021-02-25 3:09 [PATCH] KVM: nVMX: Set X86_CR4_CET in cr4_fixed1_bits if CET IBT is enabled Yang Weijiang
@ 2021-02-25 3:09 ` Yang Weijiang
2021-03-01 17:46 ` Sean Christopherson
2021-03-01 17:39 ` [PATCH] KVM: nVMX: Set X86_CR4_CET in cr4_fixed1_bits if CET IBT is enabled Sean Christopherson
1 sibling, 1 reply; 8+ messages in thread
From: Yang Weijiang @ 2021-02-25 3:09 UTC (permalink / raw)
To: pbonzini, seanjc, kvm, linux-kernel; +Cc: Yang Weijiang
These fields are rarely updated by L1 QEMU/KVM, sync them when L1 is trying to
read/write them and after they're changed. If CET guest entry-load bit is not
set by L1 guest, migrate them to L2 manaully.
Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Yang Weijiang <weijiang.yang@intel.com>
change in v2:
- Per Sean's review feedback, change CET guest states as rarely-updated fields.
And also migrate L1's CET states to L2 if the entry-load bit is not set.
- Opportunistically removed one blank line.
---
arch/x86/kvm/cpuid.c | 1 -
arch/x86/kvm/vmx/nested.c | 29 +++++++++++++++++++++++++++++
arch/x86/kvm/vmx/vmx.h | 3 +++
3 files changed, 32 insertions(+), 1 deletion(-)
diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index 46087bca9418..afc97122c05c 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -143,7 +143,6 @@ void kvm_update_cpuid_runtime(struct kvm_vcpu *vcpu)
}
vcpu->arch.guest_supported_xss =
(((u64)best->edx << 32) | best->ecx) & supported_xss;
-
} else {
vcpu->arch.guest_supported_xss = 0;
}
diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index 9728efd529a1..1703b8874fad 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -2516,6 +2516,12 @@ static void prepare_vmcs02_rare(struct vcpu_vmx *vmx, struct vmcs12 *vmcs12)
vmcs_write32(VM_ENTRY_MSR_LOAD_COUNT, vmx->msr_autoload.guest.nr);
set_cr4_guest_host_mask(vmx);
+
+ if (kvm_cet_supported()) {
+ vmcs_writel(GUEST_SSP, vmcs12->guest_ssp);
+ vmcs_writel(GUEST_S_CET, vmcs12->guest_s_cet);
+ vmcs_writel(GUEST_INTR_SSP_TABLE, vmcs12->guest_ssp_tbl);
+ }
}
/*
@@ -2556,6 +2562,15 @@ static int prepare_vmcs02(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12,
if (kvm_mpx_supported() && (!vmx->nested.nested_run_pending ||
!(vmcs12->vm_entry_controls & VM_ENTRY_LOAD_BNDCFGS)))
vmcs_write64(GUEST_BNDCFGS, vmx->nested.vmcs01_guest_bndcfgs);
+
+ if (kvm_cet_supported() && (!vmx->nested.nested_run_pending ||
+ !(vmcs12->vm_entry_controls & VM_ENTRY_LOAD_CET_STATE))) {
+ vmcs_writel(GUEST_SSP, vmx->nested.vmcs01_guest_ssp);
+ vmcs_writel(GUEST_S_CET, vmx->nested.vmcs01_guest_s_cet);
+ vmcs_writel(GUEST_INTR_SSP_TABLE,
+ vmx->nested.vmcs01_guest_ssp_tbl);
+ }
+
vmx_set_rflags(vcpu, vmcs12->guest_rflags);
/* EXCEPTION_BITMAP and CR0_GUEST_HOST_MASK should basically be the
@@ -3375,6 +3390,12 @@ enum nvmx_vmentry_status nested_vmx_enter_non_root_mode(struct kvm_vcpu *vcpu,
if (kvm_mpx_supported() &&
!(vmcs12->vm_entry_controls & VM_ENTRY_LOAD_BNDCFGS))
vmx->nested.vmcs01_guest_bndcfgs = vmcs_read64(GUEST_BNDCFGS);
+ if (kvm_cet_supported() &&
+ !(vmcs12->vm_entry_controls & VM_ENTRY_LOAD_CET_STATE)) {
+ vmx->nested.vmcs01_guest_ssp = vmcs_readl(GUEST_SSP);
+ vmx->nested.vmcs01_guest_s_cet = vmcs_readl(GUEST_S_CET);
+ vmx->nested.vmcs01_guest_ssp_tbl = vmcs_readl(GUEST_INTR_SSP_TABLE);
+ }
/*
* Overwrite vmcs01.GUEST_CR3 with L1's CR3 if EPT is disabled *and*
@@ -4001,6 +4022,9 @@ static bool is_vmcs12_ext_field(unsigned long field)
case GUEST_IDTR_BASE:
case GUEST_PENDING_DBG_EXCEPTIONS:
case GUEST_BNDCFGS:
+ case GUEST_SSP:
+ case GUEST_INTR_SSP_TABLE:
+ case GUEST_S_CET:
return true;
default:
break;
@@ -4052,6 +4076,11 @@ static void sync_vmcs02_to_vmcs12_rare(struct kvm_vcpu *vcpu,
vmcs_readl(GUEST_PENDING_DBG_EXCEPTIONS);
if (kvm_mpx_supported())
vmcs12->guest_bndcfgs = vmcs_read64(GUEST_BNDCFGS);
+ if (kvm_cet_supported()) {
+ vmcs12->guest_ssp = vmcs_readl(GUEST_SSP);
+ vmcs12->guest_s_cet = vmcs_readl(GUEST_S_CET);
+ vmcs12->guest_ssp_tbl = vmcs_readl(GUEST_INTR_SSP_TABLE);
+ }
vmx->nested.need_sync_vmcs02_to_vmcs12_rare = false;
}
diff --git a/arch/x86/kvm/vmx/vmx.h b/arch/x86/kvm/vmx/vmx.h
index 9d3a557949ac..36dc4fdb0909 100644
--- a/arch/x86/kvm/vmx/vmx.h
+++ b/arch/x86/kvm/vmx/vmx.h
@@ -155,6 +155,9 @@ struct nested_vmx {
/* to migrate it to L2 if VM_ENTRY_LOAD_DEBUG_CONTROLS is off */
u64 vmcs01_debugctl;
u64 vmcs01_guest_bndcfgs;
+ u64 vmcs01_guest_ssp;
+ u64 vmcs01_guest_s_cet;
+ u64 vmcs01_guest_ssp_tbl;
/* to migrate it to L1 if L2 writes to L1's CR8 directly */
int l1_tpr_threshold;
--
2.26.2
^ permalink raw reply related [flat|nested] 8+ messages in thread
* Re: [PATCH] KVM: nVMX: Set X86_CR4_CET in cr4_fixed1_bits if CET IBT is enabled
2021-02-25 3:09 [PATCH] KVM: nVMX: Set X86_CR4_CET in cr4_fixed1_bits if CET IBT is enabled Yang Weijiang
2021-02-25 3:09 ` [PATCH v2] KVM: nVMX: Sync L2 guest CET states between L1/L2 Yang Weijiang
@ 2021-03-01 17:39 ` Sean Christopherson
1 sibling, 0 replies; 8+ messages in thread
From: Sean Christopherson @ 2021-03-01 17:39 UTC (permalink / raw)
To: Yang Weijiang; +Cc: pbonzini, kvm, linux-kernel
On Thu, Feb 25, 2021, Yang Weijiang wrote:
> CET SHSTK and IBT are independently controlled by kernel, set X86_CR4_CET
> bit in cr4_fixed1_bits if either of them is enabled so that nested guest
> can enjoy the feature.
>
> Signed-off-by: Yang Weijiang <weijiang.yang@intel.com>
> ---
> arch/x86/kvm/vmx/vmx.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
> index 5856c5b81084..e92134ee081c 100644
> --- a/arch/x86/kvm/vmx/vmx.c
> +++ b/arch/x86/kvm/vmx/vmx.c
> @@ -7258,6 +7258,7 @@ static void nested_vmx_cr_fixed1_bits_update(struct kvm_vcpu *vcpu)
> cr4_fixed1_update(X86_CR4_UMIP, ecx, feature_bit(UMIP));
> cr4_fixed1_update(X86_CR4_LA57, ecx, feature_bit(LA57));
> cr4_fixed1_update(X86_CR4_CET, ecx, feature_bit(SHSTK));
> + cr4_fixed1_update(X86_CR4_CET, edx, feature_bit(IBT));
Ugh, what sadist put SHSTK and IBT in separate output registers.
Reviewed-by: Sean Christopherson <seanjc@google.com>
>
> #undef cr4_fixed1_update
> }
> --
> 2.26.2
>
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH v2] KVM: nVMX: Sync L2 guest CET states between L1/L2
2021-02-25 3:09 ` [PATCH v2] KVM: nVMX: Sync L2 guest CET states between L1/L2 Yang Weijiang
@ 2021-03-01 17:46 ` Sean Christopherson
2021-03-02 9:05 ` Yang Weijiang
2021-03-02 10:35 ` Vitaly Kuznetsov
0 siblings, 2 replies; 8+ messages in thread
From: Sean Christopherson @ 2021-03-01 17:46 UTC (permalink / raw)
To: Yang Weijiang; +Cc: pbonzini, kvm, linux-kernel, Vitaly Kuznetsov
+Vitaly
On Thu, Feb 25, 2021, Yang Weijiang wrote:
> These fields are rarely updated by L1 QEMU/KVM, sync them when L1 is trying to
> read/write them and after they're changed. If CET guest entry-load bit is not
> set by L1 guest, migrate them to L2 manaully.
>
> Suggested-by: Sean Christopherson <seanjc@google.com>
> Signed-off-by: Yang Weijiang <weijiang.yang@intel.com>
>
> change in v2:
> - Per Sean's review feedback, change CET guest states as rarely-updated fields.
> And also migrate L1's CET states to L2 if the entry-load bit is not set.
> - Opportunistically removed one blank line.
> ---
> arch/x86/kvm/cpuid.c | 1 -
> arch/x86/kvm/vmx/nested.c | 29 +++++++++++++++++++++++++++++
> arch/x86/kvm/vmx/vmx.h | 3 +++
> 3 files changed, 32 insertions(+), 1 deletion(-)
>
> diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
> index 46087bca9418..afc97122c05c 100644
> --- a/arch/x86/kvm/cpuid.c
> +++ b/arch/x86/kvm/cpuid.c
> @@ -143,7 +143,6 @@ void kvm_update_cpuid_runtime(struct kvm_vcpu *vcpu)
> }
> vcpu->arch.guest_supported_xss =
> (((u64)best->edx << 32) | best->ecx) & supported_xss;
> -
> } else {
> vcpu->arch.guest_supported_xss = 0;
> }
> diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
> index 9728efd529a1..1703b8874fad 100644
> --- a/arch/x86/kvm/vmx/nested.c
> +++ b/arch/x86/kvm/vmx/nested.c
> @@ -2516,6 +2516,12 @@ static void prepare_vmcs02_rare(struct vcpu_vmx *vmx, struct vmcs12 *vmcs12)
> vmcs_write32(VM_ENTRY_MSR_LOAD_COUNT, vmx->msr_autoload.guest.nr);
>
> set_cr4_guest_host_mask(vmx);
> +
> + if (kvm_cet_supported()) {
This needs to be conditioned on CET coming from vmcs12, it's on the loading of
host state on VM-Exit that is unconditional (if CET is supported).
if (kvm_cet_supported() && vmx->nested.nested_run_pending &&
(vmcs12->vm_entry_controls & VM_ENTRY_LOAD_CET_STATE)) {
I also assume these should be guarded by one of the eVMCS fields, though a quick
search of the public docs didn't provide a hit on the CET fields.
Vitaly, any idea if these will be GUEST_GRP2 or something else?
> + vmcs_writel(GUEST_SSP, vmcs12->guest_ssp);
> + vmcs_writel(GUEST_S_CET, vmcs12->guest_s_cet);
> + vmcs_writel(GUEST_INTR_SSP_TABLE, vmcs12->guest_ssp_tbl);
> + }
> }
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH v2] KVM: nVMX: Sync L2 guest CET states between L1/L2
2021-03-01 17:46 ` Sean Christopherson
@ 2021-03-02 9:05 ` Yang Weijiang
2021-03-02 9:33 ` Paolo Bonzini
2021-03-02 10:35 ` Vitaly Kuznetsov
1 sibling, 1 reply; 8+ messages in thread
From: Yang Weijiang @ 2021-03-02 9:05 UTC (permalink / raw)
To: Sean Christopherson
Cc: Yang Weijiang, pbonzini, kvm, linux-kernel, Vitaly Kuznetsov
On Mon, Mar 01, 2021 at 09:46:19AM -0800, Sean Christopherson wrote:
> +Vitaly
>
> On Thu, Feb 25, 2021, Yang Weijiang wrote:
> > These fields are rarely updated by L1 QEMU/KVM, sync them when L1 is trying to
> > read/write them and after they're changed. If CET guest entry-load bit is not
> > set by L1 guest, migrate them to L2 manaully.
> >
> > Suggested-by: Sean Christopherson <seanjc@google.com>
> > Signed-off-by: Yang Weijiang <weijiang.yang@intel.com>
> >
> > change in v2:
> > - Per Sean's review feedback, change CET guest states as rarely-updated fields.
> > And also migrate L1's CET states to L2 if the entry-load bit is not set.
> > - Opportunistically removed one blank line.
> > ---
> > arch/x86/kvm/cpuid.c | 1 -
> > arch/x86/kvm/vmx/nested.c | 29 +++++++++++++++++++++++++++++
> > arch/x86/kvm/vmx/vmx.h | 3 +++
> > 3 files changed, 32 insertions(+), 1 deletion(-)
> >
> > diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
> > index 46087bca9418..afc97122c05c 100644
> > --- a/arch/x86/kvm/cpuid.c
> > +++ b/arch/x86/kvm/cpuid.c
> > @@ -143,7 +143,6 @@ void kvm_update_cpuid_runtime(struct kvm_vcpu *vcpu)
> > }
> > vcpu->arch.guest_supported_xss =
> > (((u64)best->edx << 32) | best->ecx) & supported_xss;
> > -
> > } else {
> > vcpu->arch.guest_supported_xss = 0;
> > }
> > diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
> > index 9728efd529a1..1703b8874fad 100644
> > --- a/arch/x86/kvm/vmx/nested.c
> > +++ b/arch/x86/kvm/vmx/nested.c
> > @@ -2516,6 +2516,12 @@ static void prepare_vmcs02_rare(struct vcpu_vmx *vmx, struct vmcs12 *vmcs12)
> > vmcs_write32(VM_ENTRY_MSR_LOAD_COUNT, vmx->msr_autoload.guest.nr);
> >
> > set_cr4_guest_host_mask(vmx);
> > +
> > + if (kvm_cet_supported()) {
>
> This needs to be conditioned on CET coming from vmcs12, it's on the loading of
> host state on VM-Exit that is unconditional (if CET is supported).
>
> if (kvm_cet_supported() && vmx->nested.nested_run_pending &&
> (vmcs12->vm_entry_controls & VM_ENTRY_LOAD_CET_STATE)) {
>
Thanks Sean! Will change it.
> I also assume these should be guarded by one of the eVMCS fields, though a quick
> search of the public docs didn't provide a hit on the CET fields.
>
I got some description from MSFT as below, do you mean that:
GuestSsp uses clean field GUEST_BASIC (bit 10)
GuestSCet/GuestInterruptSspTableAddr uses GUEST_GRP1 (bit 11)
HostSCet/HostSsp/HostInterruptSspTableAddr uses HOST_GRP1 (bit 14)
If it is, should these go into separate patch series for Hyper-v nested
support? I have some pending patches for the enabling.
> Vitaly, any idea if these will be GUEST_GRP2 or something else?
>
> > + vmcs_writel(GUEST_SSP, vmcs12->guest_ssp);
> > + vmcs_writel(GUEST_S_CET, vmcs12->guest_s_cet);
> > + vmcs_writel(GUEST_INTR_SSP_TABLE, vmcs12->guest_ssp_tbl);
> > + }
> > }
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH v2] KVM: nVMX: Sync L2 guest CET states between L1/L2
2021-03-02 9:05 ` Yang Weijiang
@ 2021-03-02 9:33 ` Paolo Bonzini
0 siblings, 0 replies; 8+ messages in thread
From: Paolo Bonzini @ 2021-03-02 9:33 UTC (permalink / raw)
To: Yang Weijiang, Sean Christopherson; +Cc: kvm, linux-kernel, Vitaly Kuznetsov
On 02/03/21 10:05, Yang Weijiang wrote:
> I got some description from MSFT as below, do you mean that:
>
> GuestSsp uses clean field GUEST_BASIC (bit 10)
> GuestSCet/GuestInterruptSspTableAddr uses GUEST_GRP1 (bit 11)
> HostSCet/HostSsp/HostInterruptSspTableAddr uses HOST_GRP1 (bit 14)
>
> If it is, should these go into separate patch series for Hyper-v nested
> support? I have some pending patches for the enabling.
Yes, it should be a separate patch. The main patch however should add
the CET fields to EVMCS1_UNSUPPORTED_VMENTRY_CTRL and
EVMCS1_UNSUPPORTED_VMEXIT_CTRL.
Thanks,
Paolo
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH v2] KVM: nVMX: Sync L2 guest CET states between L1/L2
2021-03-01 17:46 ` Sean Christopherson
2021-03-02 9:05 ` Yang Weijiang
@ 2021-03-02 10:35 ` Vitaly Kuznetsov
2021-03-03 6:09 ` Yang Weijiang
1 sibling, 1 reply; 8+ messages in thread
From: Vitaly Kuznetsov @ 2021-03-02 10:35 UTC (permalink / raw)
To: Sean Christopherson, Yang Weijiang; +Cc: pbonzini, kvm, linux-kernel
Sean Christopherson <seanjc@google.com> writes:
> +Vitaly
>
> On Thu, Feb 25, 2021, Yang Weijiang wrote:
>> These fields are rarely updated by L1 QEMU/KVM, sync them when L1 is trying to
>> read/write them and after they're changed. If CET guest entry-load bit is not
>> set by L1 guest, migrate them to L2 manaully.
>>
>> Suggested-by: Sean Christopherson <seanjc@google.com>
>> Signed-off-by: Yang Weijiang <weijiang.yang@intel.com>
>>
>> change in v2:
>> - Per Sean's review feedback, change CET guest states as rarely-updated fields.
>> And also migrate L1's CET states to L2 if the entry-load bit is not set.
>> - Opportunistically removed one blank line.
>> ---
>> arch/x86/kvm/cpuid.c | 1 -
>> arch/x86/kvm/vmx/nested.c | 29 +++++++++++++++++++++++++++++
>> arch/x86/kvm/vmx/vmx.h | 3 +++
>> 3 files changed, 32 insertions(+), 1 deletion(-)
>>
>> diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
>> index 46087bca9418..afc97122c05c 100644
>> --- a/arch/x86/kvm/cpuid.c
>> +++ b/arch/x86/kvm/cpuid.c
>> @@ -143,7 +143,6 @@ void kvm_update_cpuid_runtime(struct kvm_vcpu *vcpu)
>> }
>> vcpu->arch.guest_supported_xss =
>> (((u64)best->edx << 32) | best->ecx) & supported_xss;
>> -
>> } else {
>> vcpu->arch.guest_supported_xss = 0;
>> }
>> diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
>> index 9728efd529a1..1703b8874fad 100644
>> --- a/arch/x86/kvm/vmx/nested.c
>> +++ b/arch/x86/kvm/vmx/nested.c
>> @@ -2516,6 +2516,12 @@ static void prepare_vmcs02_rare(struct vcpu_vmx *vmx, struct vmcs12 *vmcs12)
>> vmcs_write32(VM_ENTRY_MSR_LOAD_COUNT, vmx->msr_autoload.guest.nr);
>>
>> set_cr4_guest_host_mask(vmx);
>> +
>> + if (kvm_cet_supported()) {
>
> This needs to be conditioned on CET coming from vmcs12, it's on the loading of
> host state on VM-Exit that is unconditional (if CET is supported).
>
> if (kvm_cet_supported() && vmx->nested.nested_run_pending &&
> (vmcs12->vm_entry_controls & VM_ENTRY_LOAD_CET_STATE)) {
>
> I also assume these should be guarded by one of the eVMCS fields, though a quick
> search of the public docs didn't provide a hit on the CET fields.
>
> Vitaly, any idea if these will be GUEST_GRP2 or something else?
>
The latest published TLFS I see is 6.0b and it doesn't list anything CET
related in eVMCS v1.0 :-( So I agree with Paolo: we just need to adjust
EVMCS1_UNSUPPORTED_VMENTRY_CTRL/ EVMCS1_UNSUPPORTED_VMEXIT_CTRL for now
and enable it separately later.
>> + vmcs_writel(GUEST_SSP, vmcs12->guest_ssp);
>> + vmcs_writel(GUEST_S_CET, vmcs12->guest_s_cet);
>> + vmcs_writel(GUEST_INTR_SSP_TABLE, vmcs12->guest_ssp_tbl);
>> + }
>> }
>
--
Vitaly
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH v2] KVM: nVMX: Sync L2 guest CET states between L1/L2
2021-03-02 10:35 ` Vitaly Kuznetsov
@ 2021-03-03 6:09 ` Yang Weijiang
0 siblings, 0 replies; 8+ messages in thread
From: Yang Weijiang @ 2021-03-03 6:09 UTC (permalink / raw)
To: Vitaly Kuznetsov
Cc: Sean Christopherson, Yang Weijiang, pbonzini, kvm, linux-kernel
On Tue, Mar 02, 2021 at 11:35:41AM +0100, Vitaly Kuznetsov wrote:
> Sean Christopherson <seanjc@google.com> writes:
>
> > +Vitaly
> >
> > On Thu, Feb 25, 2021, Yang Weijiang wrote:
> >> These fields are rarely updated by L1 QEMU/KVM, sync them when L1 is trying to
> >> read/write them and after they're changed. If CET guest entry-load bit is not
> >> set by L1 guest, migrate them to L2 manaully.
> >>
> >> Suggested-by: Sean Christopherson <seanjc@google.com>
> >> Signed-off-by: Yang Weijiang <weijiang.yang@intel.com>
> >>
> >> change in v2:
> >> - Per Sean's review feedback, change CET guest states as rarely-updated fields.
> >> And also migrate L1's CET states to L2 if the entry-load bit is not set.
> >> - Opportunistically removed one blank line.
> >> ---
> >> arch/x86/kvm/cpuid.c | 1 -
> >> arch/x86/kvm/vmx/nested.c | 29 +++++++++++++++++++++++++++++
> >> arch/x86/kvm/vmx/vmx.h | 3 +++
> >> 3 files changed, 32 insertions(+), 1 deletion(-)
> >>
> >> diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
> >> index 46087bca9418..afc97122c05c 100644
> >> --- a/arch/x86/kvm/cpuid.c
> >> +++ b/arch/x86/kvm/cpuid.c
> >> @@ -143,7 +143,6 @@ void kvm_update_cpuid_runtime(struct kvm_vcpu *vcpu)
> >> }
> >> vcpu->arch.guest_supported_xss =
> >> (((u64)best->edx << 32) | best->ecx) & supported_xss;
> >> -
> >> } else {
> >> vcpu->arch.guest_supported_xss = 0;
> >> }
> >> diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
> >> index 9728efd529a1..1703b8874fad 100644
> >> --- a/arch/x86/kvm/vmx/nested.c
> >> +++ b/arch/x86/kvm/vmx/nested.c
> >> @@ -2516,6 +2516,12 @@ static void prepare_vmcs02_rare(struct vcpu_vmx *vmx, struct vmcs12 *vmcs12)
> >> vmcs_write32(VM_ENTRY_MSR_LOAD_COUNT, vmx->msr_autoload.guest.nr);
> >>
> >> set_cr4_guest_host_mask(vmx);
> >> +
> >> + if (kvm_cet_supported()) {
> >
> > This needs to be conditioned on CET coming from vmcs12, it's on the loading of
> > host state on VM-Exit that is unconditional (if CET is supported).
> >
> > if (kvm_cet_supported() && vmx->nested.nested_run_pending &&
> > (vmcs12->vm_entry_controls & VM_ENTRY_LOAD_CET_STATE)) {
> >
> > I also assume these should be guarded by one of the eVMCS fields, though a quick
> > search of the public docs didn't provide a hit on the CET fields.
> >
> > Vitaly, any idea if these will be GUEST_GRP2 or something else?
> >
>
> The latest published TLFS I see is 6.0b and it doesn't list anything CET
> related in eVMCS v1.0 :-( So I agree with Paolo: we just need to adjust
> EVMCS1_UNSUPPORTED_VMENTRY_CTRL/ EVMCS1_UNSUPPORTED_VMEXIT_CTRL for now
> and enable it separately later.
>
Thanks Vitaly and Paolo.
New patches have been sent to community.
> >> + vmcs_writel(GUEST_SSP, vmcs12->guest_ssp);
> >> + vmcs_writel(GUEST_S_CET, vmcs12->guest_s_cet);
> >> + vmcs_writel(GUEST_INTR_SSP_TABLE, vmcs12->guest_ssp_tbl);
> >> + }
> >> }
> >
>
> --
> Vitaly
^ permalink raw reply [flat|nested] 8+ messages in thread
end of thread, other threads:[~2021-03-03 12:56 UTC | newest]
Thread overview: 8+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-02-25 3:09 [PATCH] KVM: nVMX: Set X86_CR4_CET in cr4_fixed1_bits if CET IBT is enabled Yang Weijiang
2021-02-25 3:09 ` [PATCH v2] KVM: nVMX: Sync L2 guest CET states between L1/L2 Yang Weijiang
2021-03-01 17:46 ` Sean Christopherson
2021-03-02 9:05 ` Yang Weijiang
2021-03-02 9:33 ` Paolo Bonzini
2021-03-02 10:35 ` Vitaly Kuznetsov
2021-03-03 6:09 ` Yang Weijiang
2021-03-01 17:39 ` [PATCH] KVM: nVMX: Set X86_CR4_CET in cr4_fixed1_bits if CET IBT is enabled Sean Christopherson
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).