diff mbox series

[23/25] KVM: x86/mmu: Taking guest pa into consideration when calculate tdp level

Message ID 20240812224820.34826-24-rick.p.edgecombe@intel.com (mailing list archive)
State New, archived
Headers show
Series TDX vCPU/VM creation | expand

Commit Message

Rick Edgecombe Aug. 12, 2024, 10:48 p.m. UTC 
From: Xiaoyao Li <xiaoyao.li@intel.com>

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>
---
uAPI breakout v1:
 - New patch
---
 arch/x86/kvm/cpuid.c   | 14 ++++++++++++++
 arch/x86/kvm/cpuid.h   |  1 +
 arch/x86/kvm/mmu/mmu.c | 10 +++++++++-
 3 files changed, 24 insertions(+), 1 deletion(-)

Comments

Paolo Bonzini Sept. 10, 2024, 5:33 p.m. UTC | #1 
On 8/13/24 00:48, Rick Edgecombe wrote:
> +	int maxpa = 0;
> +
> +	if (vcpu->kvm->arch.vm_type == KVM_X86_TDX_VM)
> +		maxpa = cpuid_query_maxguestphyaddr(vcpu);

I think the "if" should be in cpuid_query_maxguestphyaddr(), or 
alternatively the test below should become an "else".  The current 
combination is not the clearest.

Otherwise,

Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>

> +	if (!maxpa)
> +		maxpa = cpuid_maxphyaddr(vcpu);
> +
diff mbox series

Patch

diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index 499479c769d8..ebebff0dbd3b 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -423,6 +423,20 @@  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
diff --git a/arch/x86/kvm/cpuid.h b/arch/x86/kvm/cpuid.h
index 5cc13d1b7991..2db458e4c450 100644
--- a/arch/x86/kvm/cpuid.h
+++ b/arch/x86/kvm/cpuid.h
@@ -39,6 +39,7 @@  bool kvm_cpuid(struct kvm_vcpu *vcpu, u32 *eax, u32 *ebx,
 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)
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index 3a00bf062a46..694edcb7ef46 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -5440,12 +5440,20 @@  void __kvm_mmu_refresh_passthrough_bits(struct kvm_vcpu *vcpu,
 
 static inline int kvm_mmu_get_tdp_level(struct kvm_vcpu *vcpu)
 {
+	int maxpa = 0;
+
+	if (vcpu->kvm->arch.vm_type == KVM_X86_TDX_VM)
+		maxpa = cpuid_query_maxguestphyaddr(vcpu);
+
+	if (!maxpa)
+		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;