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KVM: x86/cpuid: Exclude unpermitted xfeatures sizes at KVM_GET_SUPPORTED_CPUID

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With the help of xstate_get_guest_group_perm(), KVM can exclude unpermitted
xfeatures in cpuid.0xd.0.eax, in which case the corresponding xfeatures
sizes should also be matched to the permitted xfeatures.

To fix this inconsistency, the permitted_xcr0 and permitted_xss are defined
consistently, which implies 'supported' plus certain permissions for this
task, and it also fixes cpuid.0xd.1.ebx and later leaf-by-leaf queries.

Fixes: 445ecdf79b ("kvm: x86: Exclude unpermitted xfeatures at KVM_GET_SUPPORTED_CPUID")
Signed-off-by: Like Xu <likexu@tencent.com>
Message-Id: <20220125115223.33707-1-likexu@tencent.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Like Xu 2022-01-25 19:52:23 +08:00 committed by Paolo Bonzini
parent 35fe7cfbab
commit 1ffce0924a
1 changed files with 13 additions and 12 deletions
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25
arch/x86/kvm/cpuid.c
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@ -899,13 +899,14 @@ static inline int __do_cpuid_func(struct kvm_cpuid_array *array, u32 function)
}
break;
case 0xd: {
u64 guest_perm = xstate_get_guest_group_perm();
u64 permitted_xcr0 = supported_xcr0 & xstate_get_guest_group_perm();
u64 permitted_xss = supported_xss;
entry->eax &= supported_xcr0 & guest_perm;
entry->ebx = xstate_required_size(supported_xcr0, false);
entry->eax &= permitted_xcr0;
entry->ebx = xstate_required_size(permitted_xcr0, false);
entry->ecx = entry->ebx;
entry->edx &= (supported_xcr0 & guest_perm) >> 32;
if (!supported_xcr0)
entry->edx &= permitted_xcr0 >> 32;
if (!permitted_xcr0)
break;
entry = do_host_cpuid(array, function, 1);
@ -914,20 +915,20 @@ static inline int __do_cpuid_func(struct kvm_cpuid_array *array, u32 function)
cpuid_entry_override(entry, CPUID_D_1_EAX);
if (entry->eax & (F(XSAVES)|F(XSAVEC)))
entry->ebx = xstate_required_size(supported_xcr0 | supported_xss,
entry->ebx = xstate_required_size(permitted_xcr0 | permitted_xss,
true);
else {
WARN_ON_ONCE(supported_xss != 0);
WARN_ON_ONCE(permitted_xss != 0);
entry->ebx = 0;
}
entry->ecx &= supported_xss;
entry->edx &= supported_xss >> 32;
entry->ecx &= permitted_xss;
entry->edx &= permitted_xss >> 32;
for (i = 2; i < 64; ++i) {
bool s_state;
if (supported_xcr0 & BIT_ULL(i))
if (permitted_xcr0 & BIT_ULL(i))
s_state = false;
else if (supported_xss & BIT_ULL(i))
else if (permitted_xss & BIT_ULL(i))
s_state = true;
else
continue;
@ -941,7 +942,7 @@ static inline int __do_cpuid_func(struct kvm_cpuid_array *array, u32 function)
* invalid sub-leafs. Only valid sub-leafs should
* reach this point, and they should have a non-zero
* save state size. Furthermore, check whether the
* processor agrees with supported_xcr0/supported_xss
* processor agrees with permitted_xcr0/permitted_xss
* on whether this is an XCR0- or IA32_XSS-managed area.
*/
if (WARN_ON_ONCE(!entry->eax || (entry->ecx & 0x1) != s_state)) {