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[PATCH v1 4/4] KVM: MMU: Expose the LA57 feature to VM.




This patch exposes 5 level page table feature to the VM,
at the same time, the canonical virtual address checking is
extended to support both 48-bits and 57-bits address width.

Signed-off-by: Yu Zhang <yu.c.zhang@xxxxxxxxxxxxxxx>
---
 arch/x86/include/asm/kvm_host.h | 18 ++----------------
 arch/x86/kvm/cpuid.c            | 16 ++++++++++------
 arch/x86/kvm/emulate.c          | 12 ++++++------
 arch/x86/kvm/kvm_cache_regs.h   |  2 +-
 arch/x86/kvm/vmx.c              |  8 ++++----
 arch/x86/kvm/x86.c              |  7 +++++--
 arch/x86/kvm/x86.h              | 34 ++++++++++++++++++++++++++++++++++
 7 files changed, 62 insertions(+), 35 deletions(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 7e98a75..4bc7f11 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -85,8 +85,8 @@
 			  | X86_CR4_PSE | X86_CR4_PAE | X86_CR4_MCE     \
 			  | X86_CR4_PGE | X86_CR4_PCE | X86_CR4_OSFXSR | X86_CR4_PCIDE \
 			  | X86_CR4_OSXSAVE | X86_CR4_SMEP | X86_CR4_FSGSBASE \
-			  | X86_CR4_OSXMMEXCPT | X86_CR4_VMXE | X86_CR4_SMAP \
-			  | X86_CR4_PKE))
+			  | X86_CR4_OSXMMEXCPT | X86_CR4_LA57 | X86_CR4_VMXE \
+			  | X86_CR4_SMAP | X86_CR4_PKE))
 
 #define CR8_RESERVED_BITS (~(unsigned long)X86_CR8_TPR)
 
@@ -1297,20 +1297,6 @@ static inline void kvm_inject_gp(struct kvm_vcpu *vcpu, u32 error_code)
 	kvm_queue_exception_e(vcpu, GP_VECTOR, error_code);
 }
 
-static inline u64 get_canonical(u64 la)
-{
-	return ((int64_t)la << 16) >> 16;
-}
-
-static inline bool is_noncanonical_address(u64 la)
-{
-#ifdef CONFIG_X86_64
-	return get_canonical(la) != la;
-#else
-	return false;
-#endif
-}
-
 #define TSS_IOPB_BASE_OFFSET 0x66
 #define TSS_BASE_SIZE 0x68
 #define TSS_IOPB_SIZE (65536 / 8)
diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index aceacf8..2161b33 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -126,13 +126,16 @@ int kvm_update_cpuid(struct kvm_vcpu *vcpu)
 		best->ebx = xstate_required_size(vcpu->arch.xcr0, true);
 
 	/*
-	 * The existing code assumes virtual address is 48-bit in the canonical
-	 * address checks; exit if it is ever changed.
+	 * The existing code assumes virtual address is 48-bit or 57-bit in the
+	 * canonical address checks; exit if it is ever changed.
 	 */
 	best = kvm_find_cpuid_entry(vcpu, 0x80000008, 0);
-	if (best && ((best->eax & 0xff00) >> 8) != 48 &&
-		((best->eax & 0xff00) >> 8) != 0)
-		return -EINVAL;
+	if (best) {
+		int vaddr_bits = (best->eax & 0xff00) >> 8;
+
+		if (vaddr_bits != 48 && vaddr_bits != 57 && vaddr_bits != 0)
+			return -EINVAL;
+	}
 
 	/* Update physical-address width */
 	vcpu->arch.maxphyaddr = cpuid_query_maxphyaddr(vcpu);
@@ -388,7 +391,8 @@ static inline int __do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function,
 
 	/* cpuid 7.0.ecx*/
 	const u32 kvm_cpuid_7_0_ecx_x86_features =
-		F(AVX512VBMI) | F(PKU) | 0 /*OSPKE*/ | F(AVX512_VPOPCNTDQ);
+		F(AVX512VBMI) | F(LA57) | F(PKU) |
+		0 /*OSPKE*/ | F(AVX512_VPOPCNTDQ);
 
 	/* cpuid 7.0.edx*/
 	const u32 kvm_cpuid_7_0_edx_x86_features =
diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index a98b88a..50107ae 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -694,7 +694,7 @@ static __always_inline int __linearize(struct x86_emulate_ctxt *ctxt,
 	switch (mode) {
 	case X86EMUL_MODE_PROT64:
 		*linear = la;
-		if (is_noncanonical_address(la))
+		if (emul_is_noncanonical_address(la, ctxt))
 			goto bad;
 
 		*max_size = min_t(u64, ~0u, (1ull << 48) - la);
@@ -1748,8 +1748,8 @@ static int __load_segment_descriptor(struct x86_emulate_ctxt *ctxt,
 				sizeof(base3), &ctxt->exception);
 		if (ret != X86EMUL_CONTINUE)
 			return ret;
-		if (is_noncanonical_address(get_desc_base(&seg_desc) |
-					     ((u64)base3 << 32)))
+		if (emul_is_noncanonical_address(get_desc_base(&seg_desc) |
+				((u64)base3 << 32), ctxt))
 			return emulate_gp(ctxt, 0);
 	}
 load:
@@ -2840,8 +2840,8 @@ static int em_sysexit(struct x86_emulate_ctxt *ctxt)
 		ss_sel = cs_sel + 8;
 		cs.d = 0;
 		cs.l = 1;
-		if (is_noncanonical_address(rcx) ||
-		    is_noncanonical_address(rdx))
+		if (emul_is_noncanonical_address(rcx, ctxt) ||
+		    emul_is_noncanonical_address(rdx, ctxt))
 			return emulate_gp(ctxt, 0);
 		break;
 	}
@@ -3756,7 +3756,7 @@ static int em_lgdt_lidt(struct x86_emulate_ctxt *ctxt, bool lgdt)
 	if (rc != X86EMUL_CONTINUE)
 		return rc;
 	if (ctxt->mode == X86EMUL_MODE_PROT64 &&
-	    is_noncanonical_address(desc_ptr.address))
+	    emul_is_noncanonical_address(desc_ptr.address, ctxt))
 		return emulate_gp(ctxt, 0);
 	if (lgdt)
 		ctxt->ops->set_gdt(ctxt, &desc_ptr);
diff --git a/arch/x86/kvm/kvm_cache_regs.h b/arch/x86/kvm/kvm_cache_regs.h
index 762cdf2..0052317 100644
--- a/arch/x86/kvm/kvm_cache_regs.h
+++ b/arch/x86/kvm/kvm_cache_regs.h
@@ -4,7 +4,7 @@
 #define KVM_POSSIBLE_CR0_GUEST_BITS X86_CR0_TS
 #define KVM_POSSIBLE_CR4_GUEST_BITS				  \
 	(X86_CR4_PVI | X86_CR4_DE | X86_CR4_PCE | X86_CR4_OSFXSR  \
-	 | X86_CR4_OSXMMEXCPT | X86_CR4_PGE)
+	 | X86_CR4_OSXMMEXCPT | X86_CR4_LA57 | X86_CR4_PGE)
 
 static inline unsigned long kvm_register_read(struct kvm_vcpu *vcpu,
 					      enum kvm_reg reg)
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 614ade7..ee0e5b7 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -122,7 +122,7 @@ module_param_named(preemption_timer, enable_preemption_timer, bool, S_IRUGO);
 	(KVM_VM_CR0_ALWAYS_ON_UNRESTRICTED_GUEST | X86_CR0_PG | X86_CR0_PE)
 #define KVM_CR4_GUEST_OWNED_BITS				      \
 	(X86_CR4_PVI | X86_CR4_DE | X86_CR4_PCE | X86_CR4_OSFXSR      \
-	 | X86_CR4_OSXMMEXCPT | X86_CR4_TSD)
+	 | X86_CR4_OSXMMEXCPT | X86_CR4_LA57 | X86_CR4_TSD)
 
 #define KVM_PMODE_VM_CR4_ALWAYS_ON (X86_CR4_PAE | X86_CR4_VMXE)
 #define KVM_RMODE_VM_CR4_ALWAYS_ON (X86_CR4_VME | X86_CR4_PAE | X86_CR4_VMXE)
@@ -3368,7 +3368,7 @@ static int vmx_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
 		    (!msr_info->host_initiated &&
 		     !guest_cpuid_has(vcpu, X86_FEATURE_MPX)))
 			return 1;
-		if (is_noncanonical_address(data & PAGE_MASK) ||
+		if (is_noncanonical_address(data & PAGE_MASK, vcpu) ||
 		    (data & MSR_IA32_BNDCFGS_RSVD))
 			return 1;
 		vmcs_write64(GUEST_BNDCFGS, data);
@@ -7034,7 +7034,7 @@ static int get_vmx_mem_address(struct kvm_vcpu *vcpu,
 		 * non-canonical form. This is the only check on the memory
 		 * destination for long mode!
 		 */
-		exn = is_noncanonical_address(*ret);
+		exn = is_noncanonical_address(*ret, vcpu);
 	} else if (is_protmode(vcpu)) {
 		/* Protected mode: apply checks for segment validity in the
 		 * following order:
@@ -7839,7 +7839,7 @@ static int handle_invvpid(struct kvm_vcpu *vcpu)
 
 	switch (type) {
 	case VMX_VPID_EXTENT_INDIVIDUAL_ADDR:
-		if (is_noncanonical_address(operand.gla)) {
+		if (is_noncanonical_address(operand.gla, vcpu)) {
 			nested_vmx_failValid(vcpu,
 				VMXERR_INVALID_OPERAND_TO_INVEPT_INVVPID);
 			return kvm_skip_emulated_instruction(vcpu);
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index d9100c4..4935660 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -769,6 +769,9 @@ int kvm_set_cr4(struct kvm_vcpu *vcpu, unsigned long cr4)
 	if (!guest_cpuid_has(vcpu, X86_FEATURE_PKU) && (cr4 & X86_CR4_PKE))
 		return 1;
 
+	if (!guest_cpuid_has(vcpu, X86_FEATURE_LA57) && (cr4 & X86_CR4_LA57))
+		return 1;
+
 	if (is_long_mode(vcpu)) {
 		if (!(cr4 & X86_CR4_PAE))
 			return 1;
@@ -1074,7 +1077,7 @@ int kvm_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr)
 	case MSR_KERNEL_GS_BASE:
 	case MSR_CSTAR:
 	case MSR_LSTAR:
-		if (is_noncanonical_address(msr->data))
+		if (is_noncanonical_address(msr->data, vcpu))
 			return 1;
 		break;
 	case MSR_IA32_SYSENTER_EIP:
@@ -1091,7 +1094,7 @@ int kvm_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr)
 		 * value, and that something deterministic happens if the guest
 		 * invokes 64-bit SYSENTER.
 		 */
-		msr->data = get_canonical(msr->data);
+		msr->data = get_canonical(msr->data, vcpu_virt_addr_bits(vcpu));
 	}
 	return kvm_x86_ops->set_msr(vcpu, msr);
 }
diff --git a/arch/x86/kvm/x86.h b/arch/x86/kvm/x86.h
index 0107ab7..63ed0d0 100644
--- a/arch/x86/kvm/x86.h
+++ b/arch/x86/kvm/x86.h
@@ -97,6 +97,40 @@ static inline u32 bit(int bitno)
 	return 1 << (bitno & 31);
 }
 
+static inline u8 vcpu_virt_addr_bits(struct kvm_vcpu *vcpu)
+{
+	return kvm_read_cr4_bits(vcpu, X86_CR4_LA57) ? 57 : 48;
+}
+
+static inline u8 ctxt_virt_addr_bits(struct x86_emulate_ctxt *ctxt)
+{
+	return (ctxt->ops->get_cr(ctxt, 4) & X86_CR4_LA57) ? 57 : 48;
+}
+
+static inline u64 get_canonical(u64 la, u8 vaddr_bits)
+{
+	return ((int64_t)la << (64 - vaddr_bits)) >> (64 - vaddr_bits);
+}
+
+static inline bool is_noncanonical_address(u64 la, struct kvm_vcpu *vcpu)
+{
+#ifdef CONFIG_X86_64
+	return get_canonical(la, vcpu_virt_addr_bits(vcpu)) != la;
+#else
+	return false;
+#endif
+}
+
+static inline bool emul_is_noncanonical_address(u64 la,
+						struct x86_emulate_ctxt *ctxt)
+{
+#ifdef CONFIG_X86_64
+	return get_canonical(la, ctxt_virt_addr_bits(ctxt)) != la;
+#else
+	return false;
+#endif
+}
+
 static inline void vcpu_cache_mmio_info(struct kvm_vcpu *vcpu,
 					gva_t gva, gfn_t gfn, unsigned access)
 {
-- 
2.5.0