[PATCH 1/6] target-arm: kvm: save/restore mp state
From: Peter Maydell <hidden>
Date: 2015-02-25 23:36:23
Also in:
kvm, kvmarm, qemu-devel
On 26 February 2015 at 01:02, Alex Benn?e [off-list ref] wrote:
This adds the saving and restore of the current Multi-Processing state of the machine. While the KVM_GET/SET_MP_STATE API exposes a number of potential states for x86 we only use two for ARM. Either the process is running or not.
By this you mean "is the CPU in the PSCI powered down state or not", right?
quoted hunk ↗ jump to hunk
Signed-off-by: Alex Benn?e <redacted>diff --git a/target-arm/kvm.c b/target-arm/kvm.c index 23cefe9..8732854 100644 --- a/target-arm/kvm.c +++ b/target-arm/kvm.c@@ -25,6 +25,7 @@ #include "hw/arm/arm.h" const KVMCapabilityInfo kvm_arch_required_capabilities[] = { + KVM_CAP_INFO(MP_STATE),
Does this really want to be a required cap? I haven't checked, but assuming 'required' means what it says this presumably means we'll stop working on host kernels we previously ran fine on (even if migration didn't work there).
quoted hunk ↗ jump to hunk
KVM_CAP_LAST_INFO };diff --git a/target-arm/machine.c b/target-arm/machine.c index 9446e5a..70b1bc4 100644 --- a/target-arm/machine.c +++ b/target-arm/machine.c@@ -161,6 +161,34 @@ static const VMStateInfo vmstate_cpsr = { .put = put_cpsr, }; +#if defined CONFIG_KVM +static int get_mpstate(QEMUFile *f, void *opaque, size_t size) +{ + ARMCPU *cpu = opaque; + struct kvm_mp_state mp_state = { .mp_state = qemu_get_be32(f)}; + return kvm_vcpu_ioctl(CPU(cpu), KVM_SET_MP_STATE, &mp_state); +}
Won't this break if you're running a QEMU built with KVM support in TCG mode on an aarch64 host? In any case, for that configuration we should be migrating the TCG cpu->powered_off flag, which is where we keep the PSCI power state for TCG.
quoted hunk ↗ jump to hunk
+ +static void put_mpstate(QEMUFile *f, void *opaque, size_t size) +{ + ARMCPU *cpu = opaque; + struct kvm_mp_state mp_state; + int ret = kvm_vcpu_ioctl(CPU(cpu), KVM_GET_MP_STATE, &mp_state); + if (ret) { + fprintf(stderr, "%s: failed to get MP_STATE %d/%s\n", + __func__, ret, strerror(ret)); + abort(); + } + qemu_put_be32(f, mp_state.mp_state); +} + +static const VMStateInfo vmstate_mpstate = { + .name = "mpstate", + .get = get_mpstate, + .put = put_mpstate, +}; +#endif + static void cpu_pre_save(void *opaque) { ARMCPU *cpu = opaque;@@ -244,6 +272,16 @@ const VMStateDescription vmstate_arm_cpu = { VMSTATE_UINT32_ARRAY(env.regs, ARMCPU, 16), VMSTATE_UINT64_ARRAY(env.xregs, ARMCPU, 32), VMSTATE_UINT64(env.pc, ARMCPU), +#if defined CONFIG_KVM + { + .name = "mp_state", + .version_id = 0, + .size = sizeof(uint32_t), + .info = &vmstate_mpstate, + .flags = VMS_SINGLE, + .offset = 0, + }, +#endif
This means the migration format will be different on different build configurations, which seems like a really bad idea. Have you considered having the KVM state sync functions just sync the kernel's MP state into cpu->powered_off, and then migrating that flag here unconditionally?
{
.name = "cpsr",
.version_id = 0,
--
2.3.0-- PMM