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

stable inclusion
from stable-5.10.20
commit 689ceaad9423c18cf503e9b8ba42d8d1dad8711a
bugzilla: 50608

--------------------------------

[ Upstream commit 26443120 ]

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: 660a5d51 ("KVM: x86: save/load state on SMM switch")
Signed-off-by: NSean Christopherson <seanjc@google.com>
Message-Id: <20210205012458.3872687-3-seanjc@google.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NSasha Levin <sashal@kernel.org>
Signed-off-by: NChen Jun <chenjun102@huawei.com>
Acked-by: NXie XiuQi <xiexiuqi@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

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 & DR6_VOLATILE) | DR6_FIXED_1))
 		return X86EMUL_UNHANDLEABLE;
 
-	val = GET_SMSTATE(u32, smstate, 0x7f60);
+	val = GET_SMSTATE(u64, smstate, 0x7f60);
 
 	if (ctxt->ops->set_dr(ctxt, 7, (val & DR7_VOLATILE) | DR7_FIXED_1))
 		return X86EMUL_UNHANDLEABLE;