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Subject[PATCH 2/2] KVM: x86: Restore all 64 bits of DR6 and DR7 during RSM on x86-64
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Restore the full 64-bit values of DR6 and DR7 when emulating RSM on
x86-64, as defined by both Intel's SDM and AMD's APM.

Note, bits 63:32 of DR6 and DR7 are reserved, so this is a glorified nop
unless the SMM handler is poking into SMRAM, which it most definitely
shouldn't be doing since both Intel and AMD list the DR6 and DR7 fields
as read-only.

Fixes: 660a5d517aaa ("KVM: x86: save/load state on SMM switch")
Signed-off-by: Sean Christopherson <seanjc@google.com>
---
arch/x86/kvm/emulate.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index 2e6e6c39922f..72a1bd04dfe1 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -2564,12 +2564,12 @@ static int rsm_load_state_64(struct x86_emulate_ctxt *ctxt,
ctxt->_eip = GET_SMSTATE(u64, smstate, 0x7f78);
ctxt->eflags = GET_SMSTATE(u32, smstate, 0x7f70) | X86_EFLAGS_FIXED;

- val = GET_SMSTATE(u32, smstate, 0x7f68);
+ val = GET_SMSTATE(u64, smstate, 0x7f68);

if (ctxt->ops->set_dr(ctxt, 6, val))
return X86EMUL_UNHANDLEABLE;

- val = GET_SMSTATE(u32, smstate, 0x7f60);
+ val = GET_SMSTATE(u64, smstate, 0x7f60);

if (ctxt->ops->set_dr(ctxt, 7, val))
return X86EMUL_UNHANDLEABLE;
--
2.30.0.365.g02bc693789-goog
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