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KVM: x86/mmu: Taking guest pa into consideration when calculate tdp level

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For TDX, the maxpa (CPUID.0x80000008.EAX[7:0]) is fixed as native and
the max_gpa (CPUID.0x80000008.EAX[23:16]) is configurable and used
to configure the EPT level and GPAW.

Use max_gpa to determine the TDP level.

Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com>
Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Xiaoyao Li 2024-10-30 12:00:38 -07:00 committed by Paolo Bonzini
parent 488808e682
commit 20d913729c
3 changed files with 23 additions and 1 deletions
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14
arch/x86/kvm/cpuid.c
View File

@ -463,6 +463,20 @@ int cpuid_query_maxphyaddr(struct kvm_vcpu *vcpu)
return 36;
}
int cpuid_query_maxguestphyaddr(struct kvm_vcpu *vcpu)
{
struct kvm_cpuid_entry2 *best;
best = kvm_find_cpuid_entry(vcpu, 0x80000000);
if (!best || best->eax < 0x80000008)
goto not_found;
best = kvm_find_cpuid_entry(vcpu, 0x80000008);
if (best)
return (best->eax >> 16) & 0xff;
not_found:
return 0;
}
/*
* This "raw" version returns the reserved GPA bits without any adjustments for
* encryption technologies that usurp bits. The raw mask should be used if and

1
arch/x86/kvm/cpuid.h
View File

@ -59,6 +59,7 @@ void __init kvm_init_xstate_sizes(void);
u32 xstate_required_size(u64 xstate_bv, bool compacted);
int cpuid_query_maxphyaddr(struct kvm_vcpu *vcpu);
int cpuid_query_maxguestphyaddr(struct kvm_vcpu *vcpu);
u64 kvm_vcpu_reserved_gpa_bits_raw(struct kvm_vcpu *vcpu);
static inline int cpuid_maxphyaddr(struct kvm_vcpu *vcpu)

9
arch/x86/kvm/mmu/mmu.c
View File

@ -5416,12 +5416,19 @@ void __kvm_mmu_refresh_passthrough_bits(struct kvm_vcpu *vcpu,
static inline int kvm_mmu_get_tdp_level(struct kvm_vcpu *vcpu)
{
int maxpa;
if (vcpu->kvm->arch.vm_type == KVM_X86_TDX_VM)
maxpa = cpuid_query_maxguestphyaddr(vcpu);
else
maxpa = cpuid_maxphyaddr(vcpu);
/* tdp_root_level is architecture forced level, use it if nonzero */
if (tdp_root_level)
return tdp_root_level;
/* Use 5-level TDP if and only if it's useful/necessary. */
if (max_tdp_level == 5 && cpuid_maxphyaddr(vcpu) <= 48)
if (max_tdp_level == 5 && maxpa <= 48)
return 4;
return max_tdp_level;