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authorPaolo Bonzini <pbonzini@redhat.com>2015-10-14 15:25:52 +0200
committerPaolo Bonzini <pbonzini@redhat.com>2015-10-14 16:39:52 +0200
commitb10d92a54dac25a6152f1aa1ffc95c12908035ce (patch)
treea3b91faba082c51fcd49319ef355e3783494b832 /arch
parent25188b9986cf6b0cadcf1bc1d1693a2e9c50ed47 (diff)
KVM: x86: fix RSM into 64-bit protected mode
In order to get into 64-bit protected mode, you need to enable paging while EFER.LMA=1. For this to work, CS.L must be 0. Currently, we load the segments before CR0 and CR4, which means that if RSM returns into 64-bit protected mode CS.L is already 1 and everything breaks. Luckily, CS.L=0 is always the case when executing RSM, because it is forbidden to execute RSM from 64-bit protected mode. Hence it is enough to load CR0 and CR4 first, and only then the segments. Fixes: 660a5d517aaab9187f93854425c4c63f4a09195c Cc: stable@vger.kernel.org Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/kvm/emulate.c10
1 files changed, 7 insertions, 3 deletions
diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index b372a7557c16..9da95b9daf8d 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -2418,7 +2418,7 @@ static int rsm_load_state_64(struct x86_emulate_ctxt *ctxt, u64 smbase)
u64 val, cr0, cr4;
u32 base3;
u16 selector;
- int i;
+ int i, r;
for (i = 0; i < 16; i++)
*reg_write(ctxt, i) = GET_SMSTATE(u64, smbase, 0x7ff8 - i * 8);
@@ -2460,13 +2460,17 @@ static int rsm_load_state_64(struct x86_emulate_ctxt *ctxt, u64 smbase)
dt.address = GET_SMSTATE(u64, smbase, 0x7e68);
ctxt->ops->set_gdt(ctxt, &dt);
+ r = rsm_enter_protected_mode(ctxt, cr0, cr4);
+ if (r != X86EMUL_CONTINUE)
+ return r;
+
for (i = 0; i < 6; i++) {
- int r = rsm_load_seg_64(ctxt, smbase, i);
+ r = rsm_load_seg_64(ctxt, smbase, i);
if (r != X86EMUL_CONTINUE)
return r;
}
- return rsm_enter_protected_mode(ctxt, cr0, cr4);
+ return X86EMUL_CONTINUE;
}
static int em_rsm(struct x86_emulate_ctxt *ctxt)