[PATCH v3 5/5] KVM: MMU: Expose the LA57 feature to VM.

Yu Zhang
2017-08-24T12:50:49Z

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@linux.intel.com>
---
arch/x86/include/asm/kvm_host.h | 18 ++----------------
arch/x86/kvm/cpuid.c | 16 ++++++++++------
arch/x86/kvm/emulate.c | 16 +++++++++-------
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, 65 insertions(+), 36 deletions(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index bdef532..b4d4f51 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)

@@ -1300,20 +1300,6 @@ 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 83865a3..8683811 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 a89b595..16bf665 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -689,16 +689,18 @@ static __always_inline int __linearize(struct x86_emulate_ctxt *ctxt,
ulong la;
u32 lim;
u16 sel;
+ u8 va_bits;

la = seg_base(ctxt, addr.seg) + addr.ea;
*max_size = 0;
switch (mode) {
case X86EMUL_MODE_PROT64:
*linear = la;
- if (is_noncanonical_address(la))
+ va_bits = ctxt_virt_addr_bits(ctxt);
+ if (get_canonical(la, va_bits) != la)
goto bad;

- *max_size = min_t(u64, ~0u, (1ull << 48) - la);
+ *max_size = min_t(u64, ~0u, (1ull << va_bits) - la);
if (size > *max_size)
goto bad;
break;
@@ -1749,8 +1751,8 @@ 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:
@@ -2841,8 +2843,8 @@ 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;
}
@@ -3757,7 +3759,7 @@ 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 d4038a1..18be45d 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)
@@ -3373,7 +3373,7 @@ 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 79f5889..80eceb7 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 69de8bf..de1abf4 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