This is a note to let you know that I've just added the patch titled
KVM: arm64: Restore host physical timer access on hyp_panic()
to the 4.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...
The filename of the patch is: kvm-arm64-restore-host-physical-timer-access-on-hyp_panic.patch and it can be found in the queue-4.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.
From foo@baz Mon Apr 9 17:09:24 CEST 2018
From: James Morse james.morse@arm.com Date: Tue, 25 Apr 2017 18:02:45 +0100 Subject: KVM: arm64: Restore host physical timer access on hyp_panic()
From: James Morse james.morse@arm.com
[ Upstream commit e8ec032b182cd4841605de4fc297a8edffe55972 ]
When KVM panics, it hurridly restores the host context and parachutes into the host's panic() code. At some point panic() touches the physical timer/counter. Unless we are an arm64 system with VHE, this traps back to EL2. If we're lucky, we panic again.
Add a __timer_save_state() call to KVMs hyp_panic() path, this saves the guest registers and disables the traps for the host.
Fixes: 53fd5b6487e4 ("arm64: KVM: Add panic handling") Signed-off-by: James Morse james.morse@arm.com Reviewed-by: Marc Zyngier marc.zyngier@arm.com Reviewed-by: Christoffer Dall cdall@linaro.org Signed-off-by: Christoffer Dall cdall@linaro.org Signed-off-by: Sasha Levin alexander.levin@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/arm64/kvm/hyp/switch.c | 1 + 1 file changed, 1 insertion(+)
--- a/arch/arm64/kvm/hyp/switch.c +++ b/arch/arm64/kvm/hyp/switch.c @@ -404,6 +404,7 @@ void __hyp_text __noreturn __hyp_panic(v
vcpu = (struct kvm_vcpu *)read_sysreg(tpidr_el2); host_ctxt = kern_hyp_va(vcpu->arch.host_cpu_context); + __timer_save_state(vcpu); __deactivate_traps(vcpu); __deactivate_vm(vcpu); __sysreg_restore_host_state(host_ctxt);
Patches currently in stable-queue which might be from james.morse@arm.com are
queue-4.9/kvm-arm-restore-banked-registers-and-physical-timer-access-on-hyp_panic.patch queue-4.9/kvm-arm64-restore-host-physical-timer-access-on-hyp_panic.patch