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Message-ID: <20221006005125.680782-4-seanjc@google.com>
Date: Thu, 6 Oct 2022 00:51:16 +0000
From: Sean Christopherson <seanjc@...gle.com>
To: Paolo Bonzini <pbonzini@...hat.com>
Cc: kvm@...r.kernel.org, linux-kernel@...r.kernel.org,
Sean Christopherson <seanjc@...gle.com>
Subject: [PATCH 03/12] KVM: selftests: Add X86_PROPERTY_* framework to
retrieve CPUID values
Introduce X86_PROPERTY_* to allow retrieving values/properties from CPUID
leafs, e.g. MAXPHYADDR from CPUID.0x80000008. Use the same core code as
X86_FEATURE_*, the primary difference is that properties are multi-bit
values, whereas features enumerate a single bit.
Add this_cpu_has_p() to allow querying whether or not a property exists
based on the maximum leaf associated with the property, e.g. MAXPHYADDR
doesn't exist if the max leaf for 0x8000_xxxx is less than 0x8000_0008.
Use the new property infrastructure in vm_compute_max_gfn() to prove
that the code works as intended. Future patches will convert additional
selftests code.
Signed-off-by: Sean Christopherson <seanjc@...gle.com>
---
.../selftests/kvm/include/x86_64/processor.h | 68 +++++++++++++++++++
.../selftests/kvm/lib/x86_64/processor.c | 18 +++--
2 files changed, 76 insertions(+), 10 deletions(-)
diff --git a/tools/testing/selftests/kvm/include/x86_64/processor.h b/tools/testing/selftests/kvm/include/x86_64/processor.h
index 144268e30b22..55458e3d3ab4 100644
--- a/tools/testing/selftests/kvm/include/x86_64/processor.h
+++ b/tools/testing/selftests/kvm/include/x86_64/processor.h
@@ -168,6 +168,48 @@ struct kvm_x86_cpu_feature {
#define X86_FEATURE_KVM_HC_MAP_GPA_RANGE KVM_X86_CPU_FEATURE(0x40000001, 0, EAX, 16)
#define X86_FEATURE_KVM_MIGRATION_CONTROL KVM_X86_CPU_FEATURE(0x40000001, 0, EAX, 17)
+/*
+ * Same idea as X86_FEATURE_XXX, but X86_PROPERTY_XXX retrieves a multi-bit
+ * value/property as opposed to a single-bit feature. Again, pack the info
+ * into a 64-bit value to pass by value with no overhead.
+ */
+struct kvm_x86_cpu_property {
+ u32 function;
+ u8 index;
+ u8 reg;
+ u8 lo_bit;
+ u8 hi_bit;
+};
+#define KVM_X86_CPU_PROPERTY(fn, idx, gpr, low_bit, high_bit) \
+({ \
+ struct kvm_x86_cpu_property property = { \
+ .function = fn, \
+ .index = idx, \
+ .reg = KVM_CPUID_##gpr, \
+ .lo_bit = low_bit, \
+ .hi_bit = high_bit, \
+ }; \
+ \
+ static_assert(low_bit < high_bit); \
+ static_assert((fn & 0xc0000000) == 0 || \
+ (fn & 0xc0000000) == 0x40000000 || \
+ (fn & 0xc0000000) == 0x80000000 || \
+ (fn & 0xc0000000) == 0xc0000000); \
+ static_assert(idx < BIT(sizeof(property.index) * BITS_PER_BYTE)); \
+ property; \
+})
+
+#define X86_PROPERTY_MAX_BASIC_LEAF KVM_X86_CPU_PROPERTY(0, 0, EAX, 0, 31)
+
+#define X86_PROPERTY_MAX_KVM_LEAF KVM_X86_CPU_PROPERTY(0x40000000, 0, EAX, 0, 31)
+
+#define X86_PROPERTY_MAX_EXT_LEAF KVM_X86_CPU_PROPERTY(0x80000000, 0, EAX, 0, 31)
+#define X86_PROPERTY_MAX_PHY_ADDR KVM_X86_CPU_PROPERTY(0x80000008, 0, EAX, 0, 7)
+#define X86_PROPERTY_PHYS_ADDR_REDUCTION KVM_X86_CPU_PROPERTY(0x8000001F, 0, EBX, 6, 11)
+
+#define X86_PROPERTY_MAX_CENTAUR_LEAF KVM_X86_CPU_PROPERTY(0xC0000000, 0, EAX, 0, 31)
+
+
/* Page table bitfield declarations */
#define PTE_PRESENT_MASK BIT_ULL(0)
#define PTE_WRITABLE_MASK BIT_ULL(1)
@@ -449,6 +491,32 @@ static inline bool this_cpu_has(struct kvm_x86_cpu_feature feature)
feature.reg, feature.bit, feature.bit);
}
+static inline uint32_t this_cpu_property(struct kvm_x86_cpu_property property)
+{
+ return __this_cpu_has(property.function, property.index,
+ property.reg, property.lo_bit, property.hi_bit);
+}
+
+static __always_inline bool this_cpu_has_p(struct kvm_x86_cpu_property property)
+{
+ uint32_t max_leaf;
+
+ switch (property.function & 0xc0000000) {
+ case 0:
+ max_leaf = this_cpu_property(X86_PROPERTY_MAX_BASIC_LEAF);
+ break;
+ case 0x40000000:
+ max_leaf = this_cpu_property(X86_PROPERTY_MAX_KVM_LEAF);
+ break;
+ case 0x80000000:
+ max_leaf = this_cpu_property(X86_PROPERTY_MAX_EXT_LEAF);
+ break;
+ case 0xc0000000:
+ max_leaf = this_cpu_property(X86_PROPERTY_MAX_CENTAUR_LEAF);
+ }
+ return max_leaf >= property.function;
+}
+
#define SET_XMM(__var, __xmm) \
asm volatile("movq %0, %%"#__xmm : : "r"(__var) : #__xmm)
diff --git a/tools/testing/selftests/kvm/lib/x86_64/processor.c b/tools/testing/selftests/kvm/lib/x86_64/processor.c
index ca49944a6bce..fb9e90d25b60 100644
--- a/tools/testing/selftests/kvm/lib/x86_64/processor.c
+++ b/tools/testing/selftests/kvm/lib/x86_64/processor.c
@@ -1276,7 +1276,8 @@ unsigned long vm_compute_max_gfn(struct kvm_vm *vm)
{
const unsigned long num_ht_pages = 12 << (30 - vm->page_shift); /* 12 GiB */
unsigned long ht_gfn, max_gfn, max_pfn;
- uint32_t eax, ebx, ecx, edx, max_ext_leaf;
+ uint32_t eax, ebx, ecx, edx;
+ uint8_t maxphyaddr;
max_gfn = (1ULL << (vm->pa_bits - vm->page_shift)) - 1;
@@ -1299,17 +1300,14 @@ unsigned long vm_compute_max_gfn(struct kvm_vm *vm)
* reduced due to SME by bits 11:6 of CPUID[0x8000001f].EBX. Use
* the old conservative value if MAXPHYADDR is not enumerated.
*/
- cpuid(0x80000000, &eax, &ebx, &ecx, &edx);
- max_ext_leaf = eax;
- if (max_ext_leaf < 0x80000008)
+ if (!this_cpu_has_p(X86_PROPERTY_MAX_PHY_ADDR))
goto done;
- cpuid(0x80000008, &eax, &ebx, &ecx, &edx);
- max_pfn = (1ULL << ((eax & 0xff) - vm->page_shift)) - 1;
- if (max_ext_leaf >= 0x8000001f) {
- cpuid(0x8000001f, &eax, &ebx, &ecx, &edx);
- max_pfn >>= (ebx >> 6) & 0x3f;
- }
+ maxphyaddr = this_cpu_property(X86_PROPERTY_MAX_PHY_ADDR);
+ max_pfn = (1ULL << (maxphyaddr - vm->page_shift)) - 1;
+
+ if (this_cpu_has_p(X86_PROPERTY_PHYS_ADDR_REDUCTION))
+ max_pfn >>= this_cpu_property(X86_PROPERTY_PHYS_ADDR_REDUCTION);
ht_gfn = max_pfn - num_ht_pages;
done:
--
2.38.0.rc1.362.ged0d419d3c-goog
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