Messages in this thread | | | Date | Wed, 07 May 2014 18:57:24 +0300 | From | Nadav Amit <> | Subject | Re: [PATCH 5/5] KVM: x86: Fix wrong masking on relative jump/call |
| |
On 5/7/14, 5:43 PM, Bandan Das wrote: > Nadav Amit <namit@cs.technion.ac.il> writes: > >> Relative jumps and calls do the masking according to the operand size, and not >> according to the address size as the KVM emulator does today. In 64-bit mode, >> the resulting RIP is always 64-bit. Otherwise it is masked according to the >> instruction operand-size. Note that when 16-bit address size is used, bits >> 63:32 are unmodified. >> >> Signed-off-by: Nadav Amit <namit@cs.technion.ac.il> >> --- >> arch/x86/kvm/emulate.c | 4 +++- >> 1 file changed, 3 insertions(+), 1 deletion(-) >> >> diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c >> index 6833b41..e406705 100644 >> --- a/arch/x86/kvm/emulate.c >> +++ b/arch/x86/kvm/emulate.c >> @@ -506,7 +506,9 @@ static void rsp_increment(struct x86_emulate_ctxt *ctxt, int inc) >> >> static inline void jmp_rel(struct x86_emulate_ctxt *ctxt, int rel) >> { >> - register_address_increment(ctxt, &ctxt->_eip, rel); >> + /* 64-bit mode relative jumps are always 64-bit; otherwise mask */ >> + int op_bytes = ctxt->mode == X86EMUL_MODE_PROT64 ? 8 : ctxt->op_bytes; > > Just a nit, probably break this up for readability ? > I will make it more readable on the next version.
Thanks, Nadav
| |