This is a note to let you know that I've just added the patch titled
KVM: x86: clflushopt should be treated as a no-op by emulation
to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
kvm-x86-clflushopt-should-be-treated-as-a-no-op-by-emulation.patch
and it can be found in the queue-4.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 51b958e5aeb1e18c00332e0b37c5d4e95a3eff84 Mon Sep 17 00:00:00 2001
From: David Edmondson <david.edmondson@xxxxxxxxxx>
Date: Tue, 3 Nov 2020 12:04:00 +0000
Subject: KVM: x86: clflushopt should be treated as a no-op by emulation
From: David Edmondson <david.edmondson@xxxxxxxxxx>
commit 51b958e5aeb1e18c00332e0b37c5d4e95a3eff84 upstream.
The instruction emulator ignores clflush instructions, yet fails to
support clflushopt. Treat both similarly.
Fixes: 13e457e0eebf ("KVM: x86: Emulator does not decode clflush well")
Signed-off-by: David Edmondson <david.edmondson@xxxxxxxxxx>
Message-Id: <20201103120400.240882-1-david.edmondson@xxxxxxxxxx>
Reviewed-by: Joao Martins <joao.m.martins@xxxxxxxxxx>
Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/x86/kvm/emulate.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -3922,6 +3922,12 @@ static int em_clflush(struct x86_emulate
return X86EMUL_CONTINUE;
}
+static int em_clflushopt(struct x86_emulate_ctxt *ctxt)
+{
+ /* emulating clflushopt regardless of cpuid */
+ return X86EMUL_CONTINUE;
+}
+
static int em_movsxd(struct x86_emulate_ctxt *ctxt)
{
ctxt->dst.val = (s32) ctxt->src.val;
@@ -4411,7 +4417,7 @@ static const struct opcode group11[] = {
};
static const struct gprefix pfx_0f_ae_7 = {
- I(SrcMem | ByteOp, em_clflush), N, N, N,
+ I(SrcMem | ByteOp, em_clflush), I(SrcMem | ByteOp, em_clflushopt), N, N,
};
static const struct group_dual group15 = { {
Patches currently in stable-queue which might be from david.edmondson@xxxxxxxxxx are
queue-4.4/kvm-x86-clflushopt-should-be-treated-as-a-no-op-by-emulation.patch
