[PATCH] KVM: x86: fix RSM into 64-bit protected mode

From: Paolo Bonzini
Date: Wed Oct 14 2015 - 09:26:19 EST


In order to get into 64-bit protected mode, CS.L must be 0. This
is always the case when executing RSM, so it is enough to load the
segments after CR0 and CR4.

Fixes: 660a5d517aaab9187f93854425c4c63f4a09195c
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
---
arch/x86/kvm/emulate.c | 10 +++++++---
1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index e7a4fde5d631..2392541a96e6 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)
--
2.5.0

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