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[RFC,v6,85/92] kvm: x86: emulate lfence

Message ID 20190809160047.8319-86-alazar@bitdefender.com (mailing list archive)
State New, archived
Headers show
Series VM introspection | expand

Commit Message

Adalbert Lazăr Aug. 9, 2019, 4 p.m. UTC 
From: Mihai Donțu <mdontu@bitdefender.com>

This adds support for all encoding variants of lfence (0x0f 0xae 0xe[8-f]).

I did not use rmb() in case it will be made to use a different instruction
on future architectures.

Signed-off-by: Mihai Donțu <mdontu@bitdefender.com>
Signed-off-by: Adalbert Lazăr <alazar@bitdefender.com>
---
 arch/x86/kvm/emulate.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)
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Patch

diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index a2e5e63bd94a..287d3751675d 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -4168,6 +4168,12 @@  static int em_fxrstor(struct x86_emulate_ctxt *ctxt)
 	return rc;
 }
 
+static int em_lfence(struct x86_emulate_ctxt *ctxt)
+{
+	asm volatile ("lfence" ::: "memory");
+	return X86EMUL_CONTINUE;
+}
+
 static bool valid_cr(int nr)
 {
 	switch (nr) {
@@ -4554,7 +4560,7 @@  static const struct group_dual group15 = { {
 	I(ModRM | Aligned16, em_fxrstor),
 	N, N, N, N, N, GP(0, &pfx_0f_ae_7),
 }, {
-	N, N, N, N, N, N, N, N,
+	N, N, N, N, N, I(ModRM | Sse, em_lfence), N, N,
 } };
 
 static const struct gprefix pfx_0f_6f_0f_7f = {