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Subject[PATCH 6/7] KVM: x86: Clear rflags.rf on emulated instructions
Date
When an instruction is emulated RFLAGS.RF should be cleared. KVM previously did
not do so. This patch clears RFLAGS.RF after interception is done. If a fault
occurs during the instruction, RFLAGS.RF will be set by a previous patch. This
patch does not handle the case of traps/interrupts during rep-strings. Traps
are only expected to occur on debug watchpoints, and those are anyhow not
handled by the emulator.

Signed-off-by: Nadav Amit <namit@cs.technion.ac.il>
---
arch/x86/kvm/emulate.c | 3 +++
1 file changed, 3 insertions(+)

diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index cf117bf..189b8bd8 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -4640,6 +4640,7 @@ int x86_emulate_insn(struct x86_emulate_ctxt *ctxt)
/* All REP prefixes have the same first termination condition */
if (address_mask(ctxt, reg_read(ctxt, VCPU_REGS_RCX)) == 0) {
ctxt->eip = ctxt->_eip;
+ ctxt->eflags &= ~EFLG_RF;
goto done;
}
}
@@ -4682,6 +4683,8 @@ special_insn:
goto done;
}

+ ctxt->eflags &= ~EFLG_RF;
+
if (ctxt->execute) {
if (ctxt->d & Fastop) {
void (*fop)(struct fastop *) = (void *)ctxt->execute;
--
1.9.1


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