[v2,25/25] KVM: x86/mmu: Taking guest pa into consideration when calculate tdp level

Commit Message

Edgecombe, Rick P Oct. 30, 2024, 7 p.m. UTC

From: Xiaoyao Li <[e-mail]>

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 <[e-mail]>
Signed-off-by: Rick Edgecombe <[e-mail]>
---
uAPI breakout v2:
 - Use if else for cpuid_query_maxguestphyaddr() (Paolo)

uAPI breakout v1:
 - New patch
---
 arch/x86/kvm/cpuid.c   | 14 ++++++++++++++
 arch/x86/kvm/cpuid.h   |  1 +
 arch/x86/kvm/mmu/mmu.c |  9 ++++++++-
 3 files changed, 23 insertions(+), 1 deletion(-)

Patch

diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index 14be20e003f4..e7179ce8eadc 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 00570227e2ae..61b839aa3548 100644
--- a/arch/x86/kvm/cpuid.h
+++ b/arch/x86/kvm/cpuid.h
@@ -37,6 +37,7 @@  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 9a0fbec33984..2e253a488949 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -5474,12 +5474,19 @@  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;