linux/virt/kvm/arm
Oliver Upton 810f9b6f0a KVM: arm64: Handle PSCI resets before userspace touches vCPU state
[ Upstream commit 6826c6849b46aaa91300201213701eb861af4ba0 ]

The CPU_ON PSCI call takes a payload that KVM uses to configure a
destination vCPU to run. This payload is non-architectural state and not
exposed through any existing UAPI. Effectively, we have a race between
CPU_ON and userspace saving/restoring a guest: if the target vCPU isn't
ran again before the VMM saves its state, the requested PC and context
ID are lost. When restored, the target vCPU will be runnable and start
executing at its old PC.

We can avoid this race by making sure the reset payload is serviced
before userspace can access a vCPU's state.

Fixes: 358b28f09f ("arm/arm64: KVM: Allow a VCPU to fully reset itself")
Signed-off-by: Oliver Upton <oupton@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20210818202133.1106786-3-oupton@google.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-09-22 12:26:45 +02:00
..
hyp KVM: arm64: Fix 32bit PC wrap-around 2020-05-14 07:58:26 +02:00
vgic KVM: arm/arm64: Fix KVM_VGIC_V3_ADDR_TYPE_REDIST read 2021-06-23 14:41:31 +02:00
aarch32.c KVM: arm64: Synchronize sysreg state on injecting an AArch32 exception 2020-06-17 16:40:38 +02:00
arch_timer.c KVM: arm64: Treat emulated TVAL TimerValue as a signed 32-bit integer 2020-02-14 16:34:18 -05:00
arm.c KVM: arm64: Handle PSCI resets before userspace touches vCPU state 2021-09-22 12:26:45 +02:00
mmio.c KVM: arm64: Assume write fault on S1PTW permission fault on instruction fetch 2020-10-01 13:18:25 +02:00
mmu.c KVM: arm64: Fix exclusive limit for IPA size 2021-03-17 17:03:57 +01:00
perf.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 234 2019-06-19 17:09:07 +02:00
pmu.c KVM: arm64: pmu: Fix chained SW_INCR counters 2020-02-14 16:34:17 -05:00
psci.c KVM: arm64: ARM_SMCCC_ARCH_WORKAROUND_1 doesn't return SMCCC_RET_NOT_REQUIRED 2020-11-18 19:20:21 +01:00
trace.h KVM: arm/arm64: Fix TRACE_INCLUDE_PATH 2019-02-19 21:05:51 +00:00