Remove the emulator's checks for illegal CR0, CR3, and CR4 values, as
the checks are redundant, outdated, and in the case of SEV's C-bit,
broken. The emulator manually calculates MAXPHYADDR from CPUID and
neglects to mask off the C-bit. For all other checks, kvm_set_cr*() are
a superset of the emulator checks, e.g. see CR4.LA57.
Fixes: a780a3ea6282 ("KVM: X86: Fix reserved bits check for MOV to CR3")
Cc: Babu Moger <babu.moger@xxxxxxx>
Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
---
arch/x86/kvm/emulate.c | 68 +-----------------------------------------
1 file changed, 1 insertion(+), 67 deletions(-)
diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index f7970ba6219f..f4273b8e31fa 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -4230,75 +4230,9 @@ static int check_cr_read(struct x86_emulate_ctxt *ctxt)
static int check_cr_write(struct x86_emulate_ctxt *ctxt)
{
- u64 new_val = ctxt->src.val64;
- int cr = ctxt->modrm_reg;
- u64 efer = 0;
-
- static u64 cr_reserved_bits[] = {
- 0xffffffff00000000ULL,
- 0, 0, 0, /* CR3 checked later */
- CR4_RESERVED_BITS,
- 0, 0, 0,
- CR8_RESERVED_BITS,
- };
-
- if (!valid_cr(cr))
+ if (!valid_cr(ctxt->modrm_reg))
return emulate_ud(ctxt);
- if (new_val & cr_reserved_bits[cr])
- return emulate_gp(ctxt, 0);
-
- switch (cr) {
- case 0: {
- u64 cr4;
- if (((new_val & X86_CR0_PG) && !(new_val & X86_CR0_PE)) ||
- ((new_val & X86_CR0_NW) && !(new_val & X86_CR0_CD)))
- return emulate_gp(ctxt, 0);
-
- cr4 = ctxt->ops->get_cr(ctxt, 4);
- ctxt->ops->get_msr(ctxt, MSR_EFER, &efer);
-
- if ((new_val & X86_CR0_PG) && (efer & EFER_LME) &&
- !(cr4 & X86_CR4_PAE))
- return emulate_gp(ctxt, 0);
-
- break;
- }
- case 3: {
- u64 rsvd = 0;
-
- ctxt->ops->get_msr(ctxt, MSR_EFER, &efer);
- if (efer & EFER_LMA) {
- u64 maxphyaddr;
- u32 eax, ebx, ecx, edx;
-
- eax = 0x80000008;
- ecx = 0;
- if (ctxt->ops->get_cpuid(ctxt, &eax, &ebx, &ecx,
- &edx, true))
- maxphyaddr = eax & 0xff;
- else
- maxphyaddr = 36;
- rsvd = rsvd_bits(maxphyaddr, 63);
- if (ctxt->ops->get_cr(ctxt, 4) & X86_CR4_PCIDE)
- rsvd &= ~X86_CR3_PCID_NOFLUSH;
- }
-
- if (new_val & rsvd)
- return emulate_gp(ctxt, 0);
-
- break;
- }
- case 4: {
- ctxt->ops->get_msr(ctxt, MSR_EFER, &efer);
-
- if ((efer & EFER_LMA) && !(new_val & X86_CR4_PAE))
- return emulate_gp(ctxt, 0);
-
- break;
- }
- }
-
return X86EMUL_CONTINUE;
}
--
2.30.0.478.g8a0d178c01-goog
