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>