diff mbox series

[9/9] target/arm/kvm: Write CPU state back to KVM on reset

Message ID 20230929124304.13672-10-salil.mehta@huawei.com
State Superseded
Headers show
Series None | expand

Commit Message

Salil Mehta Sept. 29, 2023, 12:43 p.m. UTC 
From: Jean-Philippe Brucker <jean-philippe@linaro.org>

When a KVM vCPU is reset following a PSCI CPU_ON call, its power state
is not synchronized with KVM at the moment. Because the vCPU is not
marked dirty, we miss the call to kvm_arch_put_registers() that writes
to KVM's MP_STATE. Force mp_state synchronization.

Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
Signed-off-by: Salil Mehta <salil.mehta@huawei.com>
---
 target/arm/kvm.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

Comments

Alex Bennée Sept. 29, 2023, 2:39 p.m. UTC | #1 
Salil Mehta <salil.mehta@huawei.com> writes:

> From: Jean-Philippe Brucker <jean-philippe@linaro.org>
>
> When a KVM vCPU is reset following a PSCI CPU_ON call, its power state
> is not synchronized with KVM at the moment. Because the vCPU is not
> marked dirty, we miss the call to kvm_arch_put_registers() that writes
> to KVM's MP_STATE. Force mp_state synchronization.
>
> Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
> Signed-off-by: Salil Mehta <salil.mehta@huawei.com>

Seems reasonable:

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Salil Mehta Sept. 29, 2023, 4:01 p.m. UTC | #2 
> From: Alex Bennée <alex.bennee@linaro.org>
> Sent: Friday, September 29, 2023 3:40 PM
> To: Salil Mehta <salil.mehta@huawei.com>
> Cc: qemu-devel@nongnu.org; qemu-arm@nongnu.org; maz@kernel.org; jean-
> philippe@linaro.org; Jonathan Cameron <jonathan.cameron@huawei.com>;
> lpieralisi@kernel.org; peter.maydell@linaro.org;
> richard.henderson@linaro.org; imammedo@redhat.com; andrew.jones@linux.dev;
> david@redhat.com; philmd@linaro.org; eric.auger@redhat.com;
> oliver.upton@linux.dev; pbonzini@redhat.com; mst@redhat.com;
> will@kernel.org; gshan@redhat.com; rafael@kernel.org;
> linux@armlinux.org.uk; darren@os.amperecomputing.com;
> ilkka@os.amperecomputing.com; vishnu@os.amperecomputing.com;
> karl.heubaum@oracle.com; miguel.luis@oracle.com; salil.mehta@opnsrc.net;
> zhukeqian <zhukeqian1@huawei.com>; wangxiongfeng (C)
> <wangxiongfeng2@huawei.com>; wangyanan (Y) <wangyanan55@huawei.com>;
> jiakernel2@gmail.com; maobibo@loongson.cn; lixianglai@loongson.cn; Linuxarm
> <linuxarm@huawei.com>
> Subject: Re: [PATCH 9/9] target/arm/kvm: Write CPU state back to KVM on
> reset
> 
> 
> Salil Mehta <salil.mehta@huawei.com> writes:
> 
> > From: Jean-Philippe Brucker <jean-philippe@linaro.org>
> >
> > When a KVM vCPU is reset following a PSCI CPU_ON call, its power state
> > is not synchronized with KVM at the moment. Because the vCPU is not
> > marked dirty, we miss the call to kvm_arch_put_registers() that writes
> > to KVM's MP_STATE. Force mp_state synchronization.
> >
> > Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
> > Signed-off-by: Salil Mehta <salil.mehta@huawei.com>
> 
> Seems reasonable:
> 
> Reviewed-by: Alex Bennée <alex.bennee@linaro.org>

Thanks
Salil.
diff mbox series

Patch

diff --git a/target/arm/kvm.c b/target/arm/kvm.c
index b66b936a95..8cb70b9e7c 100644
--- a/target/arm/kvm.c
+++ b/target/arm/kvm.c
@@ -642,11 +642,12 @@  void kvm_arm_cpu_post_load(ARMCPU *cpu)
 void kvm_arm_reset_vcpu(ARMCPU *cpu)
 {
     int ret;
+    CPUState *cs = CPU(cpu);
 
     /* Re-init VCPU so that all registers are set to
      * their respective reset values.
      */
-    ret = kvm_arm_vcpu_init(CPU(cpu));
+    ret = kvm_arm_vcpu_init(cs);
     if (ret < 0) {
         fprintf(stderr, "kvm_arm_vcpu_init failed: %s\n", strerror(-ret));
         abort();
@@ -663,6 +664,11 @@  void kvm_arm_reset_vcpu(ARMCPU *cpu)
      * for the same reason we do so in kvm_arch_get_registers().
      */
     write_list_to_cpustate(cpu);
+    /*
+     * Ensure we call kvm_arch_put_registers(). The vCPU isn't marked dirty if
+     * it was parked in KVM and is now booting from a PSCI CPU_ON call.
+     */
+    cs->vcpu_dirty = true;
 }
 
 /*