linux-kernel - [PATCH 4.14 141/195] KVM: arm/arm64: Handle CPU_PM_ENTER

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: <20180215151712.834917069@linuxfoundation.org>
Date:   Thu, 15 Feb 2018 16:17:12 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org,
        Lorenzo Pieralisi <lorenzo.pieralisi@....com>,
        Christoffer Dall <christoffer.dall@...aro.org>,
        James Morse <james.morse@....com>
Subject: [PATCH 4.14 141/195] KVM: arm/arm64: Handle CPU_PM_ENTER_FAILED

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

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

From: James Morse <james.morse@....com>

commit 58d6b15e9da5042a99c9c30ad725792e4569150e upstream.

cpu_pm_enter() calls the pm notifier chain with CPU_PM_ENTER, then if
there is a failure: CPU_PM_ENTER_FAILED.

When KVM receives CPU_PM_ENTER it calls cpu_hyp_reset() which will
return us to the hyp-stub. If we subsequently get a CPU_PM_ENTER_FAILED,
KVM does nothing, leaving the CPU running with the hyp-stub, at odds
with kvm_arm_hardware_enabled.

Add CPU_PM_ENTER_FAILED as a fallthrough for CPU_PM_EXIT, this reloads
KVM based on kvm_arm_hardware_enabled. This is safe even if CPU_PM_ENTER
never gets as far as KVM, as cpu_hyp_reinit() calls cpu_hyp_reset()
to make sure the hyp-stub is loaded before reloading KVM.

Fixes: 67f691976662 ("arm64: kvm: allows kvm cpu hotplug")
CC: Lorenzo Pieralisi <lorenzo.pieralisi@....com>
Reviewed-by: Christoffer Dall <christoffer.dall@...aro.org>
Signed-off-by: James Morse <james.morse@....com>
Signed-off-by: Christoffer Dall <christoffer.dall@...aro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 virt/kvm/arm/arm.c |    1 +
 1 file changed, 1 insertion(+)

--- a/virt/kvm/arm/arm.c
+++ b/virt/kvm/arm/arm.c
@@ -1220,6 +1220,7 @@ static int hyp_init_cpu_pm_notifier(stru
 			cpu_hyp_reset();

 		return NOTIFY_OK;
+	case CPU_PM_ENTER_FAILED:
 	case CPU_PM_EXIT:
 		if (__this_cpu_read(kvm_arm_hardware_enabled))
 			/* The hardware was enabled before suspend. */