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From: Avi Kivity <>
Subject: [PATCH 4/5] KVM: Fix asm constraints with CONFIG_FRAME_POINTER=n
Date: Thu, 11 Jan 2007 10:06:30 -0000	[thread overview]
Message-ID: <> (raw)
In-Reply-To: <>

A "g" constraint may place a local variable in an %rsp-relative memory operand.
but if your assembly changes %rsp, the operand points to the wrong location.

An "r" constraint fixes that.

Thanks to Ingo Molnar for neatly bisecting the problem.

Signed-off-by: Avi Kivity <>

Index: linux-2.6/drivers/kvm/vmx.c
--- linux-2.6.orig/drivers/kvm/vmx.c
+++ linux-2.6/drivers/kvm/vmx.c
@@ -1825,7 +1825,7 @@ again:
 		"setbe %0 \n\t"
 		"popf \n\t"
-	      : "=g" (fail)
+	      : "=r" (fail)
 	      : "r"(vcpu->launched), "d"((unsigned long)HOST_RSP),
 		[rax]"i"(offsetof(struct kvm_vcpu, regs[VCPU_REGS_RAX])),

  parent reply	other threads:[~2007-01-11 10:06 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-01-11 10:02 [PATCH 0/5] KVM updates for 2.6.20 Avi Kivity
2007-01-11 10:03 ` [PATCH 1/5] KVM: Make sure there is a vcpu context loaded when destroying the mmu Avi Kivity
2007-01-11 10:04 ` [PATCH 2/5] KVM: Fix race between mmio reads and injected interrupts Avi Kivity
2007-01-11 10:05 ` [PATCH 3/5] KVM: x86 emulator: fix bit string instructions Avi Kivity
2007-01-11 10:06 ` Avi Kivity [this message]
2007-01-23  3:10   ` [PATCH 4/5] KVM: Fix asm constraints with CONFIG_FRAME_POINTER=n Herbert Xu
2007-01-11 10:07 ` [PATCH 5/5] KVM: Fix bogus pagefault on writable pages Avi Kivity

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