From: Peter Zijlstra <peterz@infradead.org>
To: David Woodhouse <dwmw2@infradead.org>,
Thomas Gleixner <tglx@linutronix.de>,
Josh Poimboeuf <jpoimboe@redhat.com>
Cc: linux-kernel@vger.kernel.org, Dave Hansen <dave.hansen@intel.com>,
Ashok Raj <ashok.raj@intel.com>,
Tim Chen <tim.c.chen@linux.intel.com>,
Andy Lutomirski <luto@kernel.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Greg KH <gregkh@linuxfoundation.org>,
Andrea Arcangeli <aarcange@redhat.com>,
Andi Kleen <ak@linux.intel.com>,
Arjan Van De Ven <arjan.van.de.ven@intel.com>,
Dan Williams <dan.j.williams@intel.com>,
Paolo Bonzini <pbonzini@redhat.com>,
Jun Nakajima <jun.nakajima@intel.com>,
Asit Mallick <asit.k.mallick@intel.com>,
Jason Baron <jbaron@akamai.com>,
rga@amazon.de, Peter Zijlstra <peterz@infradead.org>,
David Woodhouse <dwmw@amazon.co.uk>
Subject: [PATCH 1/2] x86,kvm: Fix indirect calls in emulator
Date: Thu, 25 Jan 2018 10:58:13 +0100 [thread overview]
Message-ID: <20180125095843.595615683@infradead.org> (raw)
In-Reply-To: 20180125095812.447754815@infradead.org
[-- Attachment #1: peterz-kvm-retpoline.patch --]
[-- Type: text/plain, Size: 1478 bytes --]
Replace the indirect calls with CALL_NOSPEC.
Cc: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
arch/x86/kvm/emulate.c | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -25,6 +25,7 @@
#include <asm/kvm_emulate.h>
#include <linux/stringify.h>
#include <asm/debugreg.h>
+#include <asm/nospec-branch.h>
#include "x86.h"
#include "tss.h"
@@ -1021,8 +1022,8 @@ static __always_inline u8 test_cc(unsign
void (*fop)(void) = (void *)em_setcc + 4 * (condition & 0xf);
flags = (flags & EFLAGS_MASK) | X86_EFLAGS_IF;
- asm("push %[flags]; popf; call *%[fastop]"
- : "=a"(rc) : [fastop]"r"(fop), [flags]"r"(flags));
+ asm("push %[flags]; popf; " CALL_NOSPEC
+ : "=a"(rc) : [thunk_target]"r"(fop), [flags]"r"(flags));
return rc;
}
@@ -5335,9 +5336,9 @@ static int fastop(struct x86_emulate_ctx
if (!(ctxt->d & ByteOp))
fop += __ffs(ctxt->dst.bytes) * FASTOP_SIZE;
- asm("push %[flags]; popf; call *%[fastop]; pushf; pop %[flags]\n"
+ asm("push %[flags]; popf; " CALL_NOSPEC " ; pushf; pop %[flags]\n"
: "+a"(ctxt->dst.val), "+d"(ctxt->src.val), [flags]"+D"(flags),
- [fastop]"+S"(fop), ASM_CALL_CONSTRAINT
+ [thunk_target]"+S"(fop), ASM_CALL_CONSTRAINT
: "c"(ctxt->src2.val));
ctxt->eflags = (ctxt->eflags & ~EFLAGS_MASK) | (flags & EFLAGS_MASK);
next prev parent reply other threads:[~2018-01-25 9:58 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-01-25 9:58 [PATCH 0/2] KVM retpoline fixes Peter Zijlstra
2018-01-25 9:58 ` Peter Zijlstra [this message]
2018-01-25 10:34 ` [tip:x86/pti] KVM: x86: Make indirect calls in emulator speculation safe tip-bot for Peter Zijlstra
2018-01-25 9:58 ` [PATCH 2/2] x86,vmx: Fix indirect call Peter Zijlstra
2018-01-25 10:34 ` [tip:x86/pti] KVM: VMX: Make indirect call specualation safe tip-bot for Peter Zijlstra
2018-01-25 13:19 ` [tip:x86/pti] KVM: VMX: Make indirect call speculation safe tip-bot for Peter Zijlstra
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