From: marc.zyngier@arm.com (Marc Zyngier)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] arm/arm64: KVM: detect CPU reset on CPU_PM_EXIT
Date: Thu, 20 Feb 2014 15:26:54 +0000 [thread overview]
Message-ID: <1392910014-15495-1-git-send-email-marc.zyngier@arm.com> (raw)
Commit 1fcf7ce0c602 (arm: kvm: implement CPU PM notifier) added
support for CPU power-management, using a cpu_nofigier to re-init
KVM on a CPU that entered CPU idle.
The code assumed that a CPU entering idle would actually be powered
off, loosing its state entierely, and would then need to be
reinitialized. It turns out that this is not always the case, and
some HW performs CPU PM without actually killing the core. In this
case, we try to reinitialize KVM while it still live. It ends up
badly, as reported by Andre Przywara (using a Calxeda Midway):
[ 3.663897] Kernel panic - not syncing: unexpected prefetch abort in Hyp mode at: 0x685760
[ 3.663897] unexpected data abort in Hyp mode at: 0xc067d150
[ 3.663897] unexpected HVC/SVC trap in Hyp mode at: 0xc0901dd0
The trick here is to detect if we've been through a full re-init or
not by looking at HVBAR (VBAR_EL2 on arm64). This involves
implementing the backend for __hyp_get_vectors in the main KVM HYP
code (rather small), and checking the return value against the
default one when the CPU notifier is called on CPU_PM_EXIT.
Reported-by: Andre Przywara <osp@andrep.de>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Rob Herring <rob.herring@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
arch/arm/kvm/arm.c | 3 ++-
arch/arm/kvm/interrupts.S | 7 ++++++-
arch/arm64/kvm/hyp.S | 9 +++++++--
3 files changed, 15 insertions(+), 4 deletions(-)
diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c
index 1d8248e..bd18bb8 100644
--- a/arch/arm/kvm/arm.c
+++ b/arch/arm/kvm/arm.c
@@ -878,7 +878,8 @@ static int hyp_init_cpu_pm_notifier(struct notifier_block *self,
unsigned long cmd,
void *v)
{
- if (cmd == CPU_PM_EXIT) {
+ if (cmd == CPU_PM_EXIT &&
+ __hyp_get_vectors() == hyp_default_vectors) {
cpu_init_hyp_mode(NULL);
return NOTIFY_OK;
}
diff --git a/arch/arm/kvm/interrupts.S b/arch/arm/kvm/interrupts.S
index ddc1553..9b0ff68 100644
--- a/arch/arm/kvm/interrupts.S
+++ b/arch/arm/kvm/interrupts.S
@@ -363,6 +363,11 @@ hyp_hvc:
host_switch_to_hyp:
pop {r0, r1, r2}
+ /* Check for __hyp_get_vectors */
+ cmp r0, #-1
+ mrceq p15, 4, r0, c12, c0, 0 @ get HVBAR
+ beq 1f
+
push {lr}
mrs lr, SPSR
push {lr}
@@ -378,7 +383,7 @@ THUMB( orr lr, #1)
pop {lr}
msr SPSR_csxf, lr
pop {lr}
- eret
+1: eret
guest_trap:
load_vcpu @ Load VCPU pointer to r0
diff --git a/arch/arm64/kvm/hyp.S b/arch/arm64/kvm/hyp.S
index 3b47c36..f1cbabe 100644
--- a/arch/arm64/kvm/hyp.S
+++ b/arch/arm64/kvm/hyp.S
@@ -737,7 +737,12 @@ el1_sync: // Guest trapped into EL2
pop x2, x3
pop x0, x1
- push lr, xzr
+ /* Check for __hyp_get_vectors */
+ cbnz x0, 1f
+ mrs x0, vbar_el2
+ b 2f
+
+1: push lr, xzr
/*
* Compute the function address in EL2, and shuffle the parameters.
@@ -750,7 +755,7 @@ el1_sync: // Guest trapped into EL2
blr lr
pop lr, xzr
- eret
+2: eret
el1_trap:
/*
--
1.8.3.4
next reply other threads:[~2014-02-20 15:26 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-02-20 15:26 Marc Zyngier [this message]
2014-02-20 22:35 ` [PATCH] arm/arm64: KVM: detect CPU reset on CPU_PM_EXIT Andre Przywara
2014-02-21 1:24 ` Christoffer Dall
2014-02-21 11:20 ` Marc Zyngier
2014-02-21 14:39 ` Lorenzo Pieralisi
2014-02-21 1:23 ` Christoffer Dall
2014-02-21 11:43 ` Marc Zyngier
2014-02-26 18:47 Marc Zyngier
2014-02-26 18:47 ` Marc Zyngier
2014-02-26 20:32 ` Paolo Bonzini
2014-02-26 20:32 ` Paolo Bonzini
2014-02-27 18:27 ` Paolo Bonzini
2014-02-27 18:27 ` Paolo Bonzini
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