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From: Sean Christopherson <seanjc@google.com>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: Sean Christopherson <seanjc@google.com>,
	Vitaly Kuznetsov <vkuznets@redhat.com>,
	Wanpeng Li <wanpengli@tencent.com>,
	Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>,
	kvm@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH 2/2] KVM: x86: Restore all 64 bits of DR6 and DR7 during RSM on x86-64
Date: Thu,  4 Feb 2021 17:24:58 -0800	[thread overview]
Message-ID: <20210205012458.3872687-3-seanjc@google.com> (raw)
In-Reply-To: <20210205012458.3872687-1-seanjc@google.com>

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


  parent reply	other threads:[~2021-02-05  1:26 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-02-05  1:24 [PATCH 0/2] KVM: x86: RSM emulation DR6/DR7 cleanups Sean Christopherson
2021-02-05  1:24 ` [PATCH 1/2] KVM: x86: Remove misleading DR6/DR7 adjustments from RSM emulation Sean Christopherson
2021-02-05  1:24 ` Sean Christopherson [this message]
2021-02-05  8:15   ` [PATCH 2/2] KVM: x86: Restore all 64 bits of DR6 and DR7 during RSM on x86-64 Paolo Bonzini

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