diff options
| author | Gleb Natapov <gleb@redhat.com> | 2010-02-10 14:21:34 +0200 |
|---|---|---|
| committer | Marcelo Tosatti <mtosatti@redhat.com> | 2010-03-01 12:36:11 -0300 |
| commit | d4c6a1549c056f1d817e8f6f2f97d8b44933472f (patch) | |
| tree | 0187b92c17284b598934fcdc147b08e4f71c9708 /arch/x86 | |
| parent | f850e2e603bf5a05b0aee7901857cf85715aa694 (diff) | |
KVM: x86 emulator: Fix popf emulation
POPF behaves differently depending on current CPU mode. Emulate correct
logic to prevent guest from changing flags that it can't change otherwise.
Signed-off-by: Gleb Natapov <gleb@redhat.com>
Cc: stable@kernel.org
Signed-off-by: Avi Kivity <avi@redhat.com>
Diffstat (limited to 'arch/x86')
| -rw-r--r-- | arch/x86/kvm/emulate.c | 55 |
1 files changed, 54 insertions, 1 deletions
diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c index 296e8519dc5..1782387c069 100644 --- a/arch/x86/kvm/emulate.c +++ b/arch/x86/kvm/emulate.c @@ -343,11 +343,18 @@ static u32 group2_table[] = { }; /* EFLAGS bit definitions. */ +#define EFLG_ID (1<<21) +#define EFLG_VIP (1<<20) +#define EFLG_VIF (1<<19) +#define EFLG_AC (1<<18) #define EFLG_VM (1<<17) #define EFLG_RF (1<<16) +#define EFLG_IOPL (3<<12) +#define EFLG_NT (1<<14) #define EFLG_OF (1<<11) #define EFLG_DF (1<<10) #define EFLG_IF (1<<9) +#define EFLG_TF (1<<8) #define EFLG_SF (1<<7) #define EFLG_ZF (1<<6) #define EFLG_AF (1<<4) @@ -1214,6 +1221,49 @@ static int emulate_pop(struct x86_emulate_ctxt *ctxt, return rc; } +static int emulate_popf(struct x86_emulate_ctxt *ctxt, + struct x86_emulate_ops *ops, + void *dest, int len) +{ + int rc; + unsigned long val, change_mask; + int iopl = (ctxt->eflags & X86_EFLAGS_IOPL) >> IOPL_SHIFT; + int cpl = kvm_x86_ops->get_cpl(ctxt->vcpu); + + rc = emulate_pop(ctxt, ops, &val, len); + if (rc != X86EMUL_CONTINUE) + return rc; + + change_mask = EFLG_CF | EFLG_PF | EFLG_AF | EFLG_ZF | EFLG_SF | EFLG_OF + | EFLG_TF | EFLG_DF | EFLG_NT | EFLG_RF | EFLG_AC | EFLG_ID; + + switch(ctxt->mode) { + case X86EMUL_MODE_PROT64: + case X86EMUL_MODE_PROT32: + case X86EMUL_MODE_PROT16: + if (cpl == 0) + change_mask |= EFLG_IOPL; + if (cpl <= iopl) + change_mask |= EFLG_IF; + break; + case X86EMUL_MODE_VM86: + if (iopl < 3) { + kvm_inject_gp(ctxt->vcpu, 0); + return X86EMUL_PROPAGATE_FAULT; + } + change_mask |= EFLG_IF; + break; + default: /* real mode */ + change_mask |= (EFLG_IOPL | EFLG_IF); + break; + } + + *(unsigned long *)dest = + (ctxt->eflags & ~change_mask) | (val & change_mask); + + return rc; +} + static void emulate_push_sreg(struct x86_emulate_ctxt *ctxt, int seg) { struct decode_cache *c = &ctxt->decode; @@ -2099,7 +2149,10 @@ special_insn: c->dst.type = OP_REG; c->dst.ptr = (unsigned long *) &ctxt->eflags; c->dst.bytes = c->op_bytes; - goto pop_instruction; + rc = emulate_popf(ctxt, ops, &c->dst.val, c->op_bytes); + if (rc != X86EMUL_CONTINUE) + goto done; + break; case 0xa0 ... 0xa1: /* mov */ c->dst.ptr = (unsigned long *)&c->regs[VCPU_REGS_RAX]; c->dst.val = c->src.val; |