From: Peter Xu <peterx@redhat.com>
To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org
Cc: Paolo Bonzini <pbonzini@redhat.com>,
Sean Christopherson <sean.j.christopherson@intel.com>,
peterx@redhat.com, Vitaly Kuznetsov <vkuznets@redhat.com>
Subject: [PATCH] KVM: X86: Avoid explictly fetch instruction in x86_decode_insn()
Date: Tue, 3 Mar 2020 21:16:37 -0500 [thread overview]
Message-ID: <20200304021637.17856-1-peterx@redhat.com> (raw)
insn_fetch() will always implicitly refill instruction buffer properly
when the buffer is empty, so we don't need to explicitly fetch it even
if insn_len==0 for x86_decode_insn().
Signed-off-by: Peter Xu <peterx@redhat.com>
---
arch/x86/kvm/emulate.c | 5 -----
1 file changed, 5 deletions(-)
diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index dd19fb3539e0..04f33c1ca926 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -5175,11 +5175,6 @@ int x86_decode_insn(struct x86_emulate_ctxt *ctxt, void *insn, int insn_len)
ctxt->opcode_len = 1;
if (insn_len > 0)
memcpy(ctxt->fetch.data, insn, insn_len);
- else {
- rc = __do_insn_fetch_bytes(ctxt, 1);
- if (rc != X86EMUL_CONTINUE)
- goto done;
- }
switch (mode) {
case X86EMUL_MODE_REAL:
--
2.24.1
next reply other threads:[~2020-03-04 2:17 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-04 2:16 Peter Xu [this message]
2020-03-04 2:37 [PATCH] KVM: X86: Avoid explictly fetch instruction in x86_decode_insn() linmiaohe
2020-03-04 7:30 ` Paolo Bonzini
2020-03-04 15:18 ` Peter Xu
2020-03-04 15:32 ` Peter Xu
2020-03-04 18:19 ` Paolo Bonzini
2020-03-04 20:30 ` Nadav Amit
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