KVM: x86: Restore all 64 bits of DR6 and DR7 during RSM on x86-64

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>
Message-Id: <20210205012458.3872687-3-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index b5f433d01caa59f662cef90ba1e024aaff39a192..f7970ba6219fc52887a4b6b3757ef6de8686ce8d 100644 (file)
--- 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;