From 95c077c91900c1420cd4f0be996ffeea6fb6cec8 Mon Sep 17 00:00:00 2001 From: Jan Kiszka Date: Mon, 27 Dec 2010 15:58:23 +0100 Subject: kvm: x86: Prevent sign extension of DR7 in guest debugging mode This unbreaks guest debugging when the 4th hardware breakpoint used for guest debugging is a watchpoint of 4 or 8 byte lenght. The 31st bit of DR7 is set in that case and used to cause a sign extension to the high word which was breaking the guest state (vm entry failure). Signed-off-by: Jan Kiszka Signed-off-by: Avi Kivity --- target-i386/kvm.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/target-i386/kvm.c b/target-i386/kvm.c index 7e5982b132..85edaccad1 100644 --- a/target-i386/kvm.c +++ b/target-i386/kvm.c @@ -1686,7 +1686,7 @@ void kvm_arch_update_guest_debug(CPUState *env, struct kvm_guest_debug *dbg) dbg->arch.debugreg[n] = hw_breakpoint[n].addr; dbg->arch.debugreg[7] |= (2 << (n * 2)) | (type_code[hw_breakpoint[n].type] << (16 + n*4)) | - (len_code[hw_breakpoint[n].len] << (18 + n*4)); + ((uint32_t)len_code[hw_breakpoint[n].len] << (18 + n*4)); } } /* Legal xcr0 for loading */ -- cgit v1.2.3