diff options
| author | Nadav Amit <namit@cs.technion.ac.il> | 2014-12-25 02:52:16 +0200 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2015-01-09 10:24:11 +0100 |
| commit | c205fb7d7d4f81e46fc577b707ceb9e356af1456 (patch) | |
| tree | b73dbbae61efb80a231368f88f319688bc71d8b1 /arch/x86 | |
| parent | 7e71a59b250330fd52ee7293eb9d31952f16682e (diff) | |
| download | linux-c205fb7d7d4f81e46fc577b707ceb9e356af1456.tar.bz2 | |
KVM: x86: #PF error-code on R/W operations is wrong
When emulating an instruction that reads the destination memory operand (i.e.,
instructions without the Mov flag in the emulator), the operand is first read.
If a page-fault is detected in this phase, the error-code which would be
delivered to the VM does not indicate that the access that caused the exception
is a write one. This does not conform with real hardware, and may cause the VM
to enter the page-fault handler twice for no reason (once for read, once for
write).
Signed-off-by: Nadav Amit <namit@cs.technion.ac.il>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86')
| -rw-r--r-- | arch/x86/include/asm/kvm_host.h | 12 | ||||
| -rw-r--r-- | arch/x86/kvm/emulate.c | 6 | ||||
| -rw-r--r-- | arch/x86/kvm/mmu.h | 12 |
3 files changed, 17 insertions, 13 deletions
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index cb19d05af3cd..97a5dd0222c8 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -160,6 +160,18 @@ enum { #define DR7_FIXED_1 0x00000400 #define DR7_VOLATILE 0xffff2bff +#define PFERR_PRESENT_BIT 0 +#define PFERR_WRITE_BIT 1 +#define PFERR_USER_BIT 2 +#define PFERR_RSVD_BIT 3 +#define PFERR_FETCH_BIT 4 + +#define PFERR_PRESENT_MASK (1U << PFERR_PRESENT_BIT) +#define PFERR_WRITE_MASK (1U << PFERR_WRITE_BIT) +#define PFERR_USER_MASK (1U << PFERR_USER_BIT) +#define PFERR_RSVD_MASK (1U << PFERR_RSVD_BIT) +#define PFERR_FETCH_MASK (1U << PFERR_FETCH_BIT) + /* apic attention bits */ #define KVM_APIC_CHECK_VAPIC 0 /* diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c index d949287ed010..ef23c1e5fa9f 100644 --- a/arch/x86/kvm/emulate.c +++ b/arch/x86/kvm/emulate.c @@ -4909,8 +4909,12 @@ int x86_emulate_insn(struct x86_emulate_ctxt *ctxt) /* optimisation - avoid slow emulated read if Mov */ rc = segmented_read(ctxt, ctxt->dst.addr.mem, &ctxt->dst.val, ctxt->dst.bytes); - if (rc != X86EMUL_CONTINUE) + if (rc != X86EMUL_CONTINUE) { + if (rc == X86EMUL_PROPAGATE_FAULT && + ctxt->exception.vector == PF_VECTOR) + ctxt->exception.error_code |= PFERR_WRITE_MASK; goto done; + } } ctxt->dst.orig_val = ctxt->dst.val; diff --git a/arch/x86/kvm/mmu.h b/arch/x86/kvm/mmu.h index a7f9a121690d..c7d65637c851 100644 --- a/arch/x86/kvm/mmu.h +++ b/arch/x86/kvm/mmu.h @@ -44,18 +44,6 @@ #define PT_DIRECTORY_LEVEL 2 #define PT_PAGE_TABLE_LEVEL 1 -#define PFERR_PRESENT_BIT 0 -#define PFERR_WRITE_BIT 1 -#define PFERR_USER_BIT 2 -#define PFERR_RSVD_BIT 3 -#define PFERR_FETCH_BIT 4 - -#define PFERR_PRESENT_MASK (1U << PFERR_PRESENT_BIT) -#define PFERR_WRITE_MASK (1U << PFERR_WRITE_BIT) -#define PFERR_USER_MASK (1U << PFERR_USER_BIT) -#define PFERR_RSVD_MASK (1U << PFERR_RSVD_BIT) -#define PFERR_FETCH_MASK (1U << PFERR_FETCH_BIT) - static inline u64 rsvd_bits(int s, int e) { return ((1ULL << (e - s + 1)) - 1) << s; |