KVM: x86: Add X86EMUL_F_MSR and X86EMUL_F_DT_LOAD to aid canonical checks

Add emulation flags for MSR accesses and Descriptor Tables loads, and pass
the new flags as appropriate to emul_is_noncanonical_address().  The flags
will be used to perform the correct canonical check, as the type of access
affects whether or not CR4.LA57 is consulted when determining the canonical
bit.

No functional change is intended.

Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Link: https://lore.kernel.org/r/20240906221824.491834-3-mlevitsk@redhat.com
[sean: split to separate patch, massage changelog]
Signed-off-by: Sean Christopherson <seanjc@google.com>

diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index 3ce83f57d267d7115874f5f2c42652e33a43097c..60986f67c35a886f07c8556d7d3511408f9567d3 100644 (file)
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -651,9 +651,10 @@ static inline u8 ctxt_virt_addr_bits(struct x86_emulate_ctxt *ctxt)
 }
 
 static inline bool emul_is_noncanonical_address(u64 la,
-                                               struct x86_emulate_ctxt *ctxt)
+                                               struct x86_emulate_ctxt *ctxt,
+                                               unsigned int flags)
 {
-       return !ctxt->ops->is_canonical_addr(ctxt, la);
+       return !ctxt->ops->is_canonical_addr(ctxt, la, flags);
 }
 
 /*
@@ -1733,7 +1734,8 @@ static int __load_segment_descriptor(struct x86_emulate_ctxt *ctxt,
                if (ret != X86EMUL_CONTINUE)
                        return ret;
                if (emul_is_noncanonical_address(get_desc_base(&seg_desc) |
-                                                ((u64)base3 << 32), ctxt))
+                                                ((u64)base3 << 32), ctxt,
+                                                X86EMUL_F_DT_LOAD))
                        return emulate_gp(ctxt, err_code);
        }
 
@@ -2516,8 +2518,8 @@ static int em_sysexit(struct x86_emulate_ctxt *ctxt)
                ss_sel = cs_sel + 8;
                cs.d = 0;
                cs.l = 1;
-               if (emul_is_noncanonical_address(rcx, ctxt) ||
-                   emul_is_noncanonical_address(rdx, ctxt))
+               if (emul_is_noncanonical_address(rcx, ctxt, 0) ||
+                   emul_is_noncanonical_address(rdx, ctxt, 0))
                        return emulate_gp(ctxt, 0);
                break;
        }
@@ -3494,7 +3496,8 @@ static int em_lgdt_lidt(struct x86_emulate_ctxt *ctxt, bool lgdt)
        if (rc != X86EMUL_CONTINUE)
                return rc;
        if (ctxt->mode == X86EMUL_MODE_PROT64 &&
-           emul_is_noncanonical_address(desc_ptr.address, ctxt))
+           emul_is_noncanonical_address(desc_ptr.address, ctxt,
+                                        X86EMUL_F_DT_LOAD))
                return emulate_gp(ctxt, 0);
        if (lgdt)
                ctxt->ops->set_gdt(ctxt, &desc_ptr);

diff --git a/arch/x86/kvm/kvm_emulate.h b/arch/x86/kvm/kvm_emulate.h
index 1b1843ff210fd201f9083e55489c82a39ea4e6ff..10495fffb8905ca0836cc7eba8e8439ff86eadd9 100644 (file)
--- a/arch/x86/kvm/kvm_emulate.h
+++ b/arch/x86/kvm/kvm_emulate.h
@@ -94,6 +94,8 @@ struct x86_instruction_info {
 #define X86EMUL_F_FETCH                        BIT(1)
 #define X86EMUL_F_IMPLICIT             BIT(2)
 #define X86EMUL_F_INVLPG               BIT(3)
+#define X86EMUL_F_MSR                  BIT(4)
+#define X86EMUL_F_DT_LOAD              BIT(5)
 
 struct x86_emulate_ops {
        void (*vm_bugged)(struct x86_emulate_ctxt *ctxt);
@@ -236,7 +238,8 @@ struct x86_emulate_ops {
        gva_t (*get_untagged_addr)(struct x86_emulate_ctxt *ctxt, gva_t addr,
                                   unsigned int flags);
 
-       bool (*is_canonical_addr)(struct x86_emulate_ctxt *ctxt, gva_t addr);
+       bool (*is_canonical_addr)(struct x86_emulate_ctxt *ctxt, gva_t addr,
+                                 unsigned int flags);
 };
 
 /* Type, address-of, and value of an instruction's operand. */

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index cd06c1d9a1f1b24fd18f089f47fd9c5b1855aaa2..a4ac80d770316acb2d9b31ea4988bcc097974392 100644 (file)
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -8620,7 +8620,7 @@ static gva_t emulator_get_untagged_addr(struct x86_emulate_ctxt *ctxt,
 }
 
 static bool emulator_is_canonical_addr(struct x86_emulate_ctxt *ctxt,
-                                      gva_t addr)
+                                      gva_t addr, unsigned int flags)
 {
        return !is_noncanonical_address(addr, emul_to_vcpu(ctxt));
 }