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| author | Marc Zyngier <marc.zyngier@arm.com> | 2014-02-26 22:47:36 +0400 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2014-02-27 22:27:10 +0400 |
| commit | b20c9f29c5c25921c6ad18b50d4b61e6d181c3cc (patch) | |
| tree | 1579f109f281d150f3a8b415f1651c384c70ec9b /arch/arm/kvm | |
| parent | 404381c5839d67aa0c275ad1da96ef3d3928ca2c (diff) | |
| download | linux-b20c9f29c5c25921c6ad18b50d4b61e6d181c3cc.tar.xz | |
arm/arm64: KVM: detect CPU reset on CPU_PM_EXIT
Commit 1fcf7ce0c602 (arm: kvm: implement CPU PM notifier) added
support for CPU power-management, using a cpu_notifier 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 is 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>
Tested-by: Andre Przywara <osp@andrep.de>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Rob Herring <rob.herring@linaro.org>
Acked-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/arm/kvm')
| -rw-r--r-- | arch/arm/kvm/arm.c | 3 | ||||
| -rw-r--r-- | arch/arm/kvm/interrupts.S | 11 |
2 files changed, 12 insertions, 2 deletions
diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c index 1d8248ea5669..bd18bb8b2770 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 ddc15539bad2..0d68d4073068 100644 --- a/arch/arm/kvm/interrupts.S +++ b/arch/arm/kvm/interrupts.S @@ -220,6 +220,10 @@ after_vfp_restore: * in Hyp mode (see init_hyp_mode in arch/arm/kvm/arm.c). Return values are * passed in r0 and r1. * + * A function pointer with a value of 0xffffffff has a special meaning, + * and is used to implement __hyp_get_vectors in the same way as in + * arch/arm/kernel/hyp_stub.S. + * * The calling convention follows the standard AAPCS: * r0 - r3: caller save * r12: caller save @@ -363,6 +367,11 @@ 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 +387,7 @@ THUMB( orr lr, #1) pop {lr} msr SPSR_csxf, lr pop {lr} - eret +1: eret guest_trap: load_vcpu @ Load VCPU pointer to r0 |