diff options
Diffstat (limited to 'debian/patches-rt/0211-KVM-arm-arm64-downgrade-preempt_disable-d-region-to-.patch')
| -rw-r--r-- | debian/patches-rt/0211-KVM-arm-arm64-downgrade-preempt_disable-d-region-to-.patch | 59 |
1 files changed, 59 insertions, 0 deletions
diff --git a/debian/patches-rt/0211-KVM-arm-arm64-downgrade-preempt_disable-d-region-to-.patch b/debian/patches-rt/0211-KVM-arm-arm64-downgrade-preempt_disable-d-region-to-.patch new file mode 100644 index 000000000..a49a4c01e --- /dev/null +++ b/debian/patches-rt/0211-KVM-arm-arm64-downgrade-preempt_disable-d-region-to-.patch @@ -0,0 +1,59 @@ +From e3788b349ef7d4161dc666a0aca9fc054c913c04 Mon Sep 17 00:00:00 2001 +From: Josh Cartwright <joshc@ni.com> +Date: Thu, 11 Feb 2016 11:54:01 -0600 +Subject: [PATCH 211/347] KVM: arm/arm64: downgrade preempt_disable()d region + to migrate_disable() +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/4.19/older/patches-4.19.246-rt110.tar.xz + +kvm_arch_vcpu_ioctl_run() disables the use of preemption when updating +the vgic and timer states to prevent the calling task from migrating to +another CPU. It does so to prevent the task from writing to the +incorrect per-CPU GIC distributor registers. + +On -rt kernels, it's possible to maintain the same guarantee with the +use of migrate_{disable,enable}(), with the added benefit that the +migrate-disabled region is preemptible. Update +kvm_arch_vcpu_ioctl_run() to do so. + +Cc: Christoffer Dall <christoffer.dall@linaro.org> +Reported-by: Manish Jaggi <Manish.Jaggi@caviumnetworks.com> +Signed-off-by: Josh Cartwright <joshc@ni.com> +Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> +--- + virt/kvm/arm/arm.c | 6 +++--- + 1 file changed, 3 insertions(+), 3 deletions(-) + +diff --git a/virt/kvm/arm/arm.c b/virt/kvm/arm/arm.c +index b943ec5345cb..ddc6db1e8cd2 100644 +--- a/virt/kvm/arm/arm.c ++++ b/virt/kvm/arm/arm.c +@@ -725,7 +725,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run) + * involves poking the GIC, which must be done in a + * non-preemptible context. + */ +- preempt_disable(); ++ migrate_disable(); + + kvm_pmu_flush_hwstate(vcpu); + +@@ -774,7 +774,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run) + kvm_timer_sync_hwstate(vcpu); + kvm_vgic_sync_hwstate(vcpu); + local_irq_enable(); +- preempt_enable(); ++ migrate_enable(); + continue; + } + +@@ -852,7 +852,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run) + /* Exit types that need handling before we can be preempted */ + handle_exit_early(vcpu, run, ret); + +- preempt_enable(); ++ migrate_enable(); + + ret = handle_exit(vcpu, run, ret); + } +-- +2.36.1 + |