linux-kernel - [PATCH 3.12 45/63] arm/arm64: KVM: Complete WFI/WFE instructions

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <b86185fb902b2f976f1910174a1b9b7b5a958ccb.1430387326.git.jslaby@suse.cz>
Date:	Thu, 30 Apr 2015 14:12:14 +0200
From:	Jiri Slaby <jslaby@...e.cz>
To:	stable@...r.kernel.org
Cc:	linux-kernel@...r.kernel.org,
	Christoffer Dall <christoffer.dall@...aro.org>,
	Ard Biesheuvel <ard.biesheuvel@...aro.org>,
	Shannon Zhao <shannon.zhao@...aro.org>,
	Jiri Slaby <jslaby@...e.cz>
Subject: [PATCH 3.12 45/63] arm/arm64: KVM: Complete WFI/WFE instructions

From: Christoffer Dall <christoffer.dall@...aro.org>

3.12-stable review patch.  If anyone has any objections, please let me know.

===============

commit 05e0127f9e362b36aa35f17b1a3d52bca9322a3a upstream.

The architecture specifies that when the processor wakes up from a WFE
or WFI instruction, the instruction is considered complete, however we
currrently return to EL1 (or EL0) at the WFI/WFE instruction itself.

While most guests may not be affected by this because their local
exception handler performs an exception returning setting the event bit
or with an interrupt pending, some guests like UEFI will get wedged due
this little mishap.

Simply skip the instruction when we have completed the emulation.

Cc: <stable@...r.kernel.org>
Acked-by: Marc Zyngier <marc.zyngier@....com>
Cc: Ard Biesheuvel <ard.biesheuvel@...aro.org>
Signed-off-by: Christoffer Dall <christoffer.dall@...aro.org>
Signed-off-by: Shannon Zhao <shannon.zhao@...aro.org>
Signed-off-by: Jiri Slaby <jslaby@...e.cz>
---
 arch/arm/kvm/handle_exit.c   | 2 ++
 arch/arm64/kvm/handle_exit.c | 2 ++
 2 files changed, 4 insertions(+)

diff --git a/arch/arm/kvm/handle_exit.c b/arch/arm/kvm/handle_exit.c
index 0de91fc6de0f..ec4fa868a7ba 100644
--- a/arch/arm/kvm/handle_exit.c
+++ b/arch/arm/kvm/handle_exit.c
@@ -89,6 +89,8 @@ static int kvm_handle_wfx(struct kvm_vcpu *vcpu, struct kvm_run *run)
 	else
 		kvm_vcpu_block(vcpu);
 
+	kvm_skip_instr(vcpu, kvm_vcpu_trap_il_is32bit(vcpu));
+
 	return 1;
 }
 
diff --git a/arch/arm64/kvm/handle_exit.c b/arch/arm64/kvm/handle_exit.c
index df84d7bcc7df..ab1ec62dd3e5 100644
--- a/arch/arm64/kvm/handle_exit.c
+++ b/arch/arm64/kvm/handle_exit.c
@@ -62,6 +62,8 @@ static int kvm_handle_wfx(struct kvm_vcpu *vcpu, struct kvm_run *run)
 	else
 		kvm_vcpu_block(vcpu);
 
+	kvm_skip_instr(vcpu, kvm_vcpu_trap_il_is32bit(vcpu));
+
 	return 1;
 }
 
-- 
2.3.5

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/