This patch adds emulation of PSCI v0.2 CPU_SUSPEND function call for KVM ARM/ARM64. This is a VCPU-level function call which can suspend current VCPU or all VCPUs within current VCPU's affinity level. The CPU_SUSPEND emulation is not tested much because currently there is no CPUIDLE driver in Linux kernel that uses PSCI CPU_SUSPEND. The PSCI CPU_SUSPEND implementation in ARM64 kernel was tested using a Simple CPUIDLE driver which is not published due to unstable DT-bindings for PSCI. (For more info, http://lwn.net/Articles/574950/) Even if we had stable DT-bindings for PSCI and CPUIDLE driver that uses PSCI CPU_SUSPEND then still we need to define SUSPEND states for KVM ARM/ARM64. Due to this, the CPU_SUSPEND emulation added by this patch only pause a VCPU and to wakeup a VCPU we need to explicity call PSCI CPU_ON from Guest. Signed-off-by: Anup Patel <anup.patel@xxxxxxxxxx> Signed-off-by: Pranavkumar Sawargaonkar <pranavkumar@xxxxxxxxxx> --- arch/arm/include/asm/kvm_host.h | 5 +++ arch/arm/include/asm/kvm_psci.h | 1 + arch/arm/kvm/psci.c | 88 +++++++++++++++++++++++++++++++++++-- arch/arm/kvm/reset.c | 4 ++ arch/arm64/include/asm/kvm_host.h | 5 +++ arch/arm64/include/asm/kvm_psci.h | 1 + arch/arm64/kvm/reset.c | 4 ++ 7 files changed, 104 insertions(+), 4 deletions(-) diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h index 193ceaf..2cc36a6 100644 --- a/arch/arm/include/asm/kvm_host.h +++ b/arch/arm/include/asm/kvm_host.h @@ -131,6 +131,11 @@ struct kvm_vcpu_arch { /* Don't run the guest on this vcpu */ bool pause; + /* PSCI suspend state */ + bool suspend; + u32 suspend_entry; + u32 suspend_context_id; + /* IO related fields */ struct kvm_decode mmio_decode; diff --git a/arch/arm/include/asm/kvm_psci.h b/arch/arm/include/asm/kvm_psci.h index 6bda945..6a05ada 100644 --- a/arch/arm/include/asm/kvm_psci.h +++ b/arch/arm/include/asm/kvm_psci.h @@ -22,6 +22,7 @@ #define KVM_ARM_PSCI_0_2 2 int kvm_psci_version(struct kvm_vcpu *vcpu); +void kvm_psci_reset(struct kvm_vcpu *vcpu); int kvm_psci_call(struct kvm_vcpu *vcpu); #endif /* __ARM_KVM_PSCI_H__ */ diff --git a/arch/arm/kvm/psci.c b/arch/arm/kvm/psci.c index 675866e..482b0f6 100644 --- a/arch/arm/kvm/psci.c +++ b/arch/arm/kvm/psci.c @@ -15,6 +15,7 @@ * along with this program. If not, see <http://www.gnu.org/licenses/>. */ +#include <linux/smp.h> #include <linux/kvm_host.h> #include <linux/wait.h> @@ -27,9 +28,81 @@ * as described in ARM document number ARM DEN 0022A. */ +struct psci_suspend_info { + struct kvm_vcpu *vcpu; + unsigned long saved_entry; + unsigned long saved_context_id; +}; + +static void psci_do_suspend(void *context) +{ + struct psci_suspend_info *sinfo = context; + + sinfo->vcpu->arch.pause = true; + sinfo->vcpu->arch.suspend = true; + sinfo->vcpu->arch.suspend_entry = sinfo->saved_entry; + sinfo->vcpu->arch.suspend_context_id = sinfo->saved_context_id; +} + +static unsigned long kvm_psci_vcpu_suspend(struct kvm_vcpu *vcpu) +{ + int i; + unsigned long mpidr; + unsigned long target_affinity; + unsigned long target_affinity_mask; + unsigned long lowest_affinity_level; + struct kvm *kvm = vcpu->kvm; + struct kvm_vcpu *tmp; + struct psci_suspend_info sinfo; + + target_affinity = kvm_vcpu_get_mpidr(vcpu); + lowest_affinity_level = (*vcpu_reg(vcpu, 1) >> 24) & 0x3; + + /* Determine target affinity mask */ + target_affinity_mask = MPIDR_HWID_BITMASK; + switch (lowest_affinity_level) { + case 0: /* All affinity levels are valid */ + target_affinity_mask &= ~0x0UL; + break; + case 1: /* Aff0 ignored */ + target_affinity_mask &= ~0xFFUL; + break; + case 2: /* Aff0 and Aff1 ignored */ + target_affinity_mask &= ~0xFFFFUL; + break; + case 3: /* Aff0, Aff1, and Aff2 ignored */ + target_affinity_mask &= ~0xFFFFFFUL; + break; + default: + return KVM_PSCI_RET_INVAL; + }; + + /* Ignore other bits of target affinity */ + target_affinity &= target_affinity_mask; + + /* Prepare suspend info */ + sinfo.vcpu = NULL; + sinfo.saved_entry = *vcpu_reg(vcpu, 2); + sinfo.saved_context_id = *vcpu_reg(vcpu, 3); + + /* Suspend all VCPUs within target affinity */ + kvm_for_each_vcpu(i, tmp, kvm) { + mpidr = kvm_vcpu_get_mpidr(tmp); + if (((mpidr & target_affinity_mask) == target_affinity) && + !tmp->arch.suspend) { + sinfo.vcpu = tmp; + smp_call_function_single(tmp->cpu, + psci_do_suspend, &sinfo, 1); + } + } + + return KVM_PSCI_RET_SUCCESS; +} + static void kvm_psci_vcpu_off(struct kvm_vcpu *vcpu) { vcpu->arch.pause = true; + vcpu->arch.suspend = false; } static unsigned long kvm_psci_vcpu_on(struct kvm_vcpu *source_vcpu, @@ -179,6 +252,10 @@ static int kvm_psci_0_2_call(struct kvm_vcpu *vcpu) */ val = 2; break; + case KVM_PSCI_0_2_FN_CPU_SUSPEND: + case KVM_PSCI_0_2_FN64_CPU_SUSPEND: + val = kvm_psci_vcpu_suspend(vcpu); + break; case KVM_PSCI_0_2_FN_CPU_OFF: kvm_psci_vcpu_off(vcpu); val = KVM_PSCI_RET_SUCCESS; @@ -216,10 +293,6 @@ static int kvm_psci_0_2_call(struct kvm_vcpu *vcpu) val = KVM_PSCI_RET_SUCCESS; ret = 0; break; - case KVM_PSCI_0_2_FN_CPU_SUSPEND: - case KVM_PSCI_0_2_FN64_CPU_SUSPEND: - val = KVM_PSCI_RET_NI; - break; default: return -EINVAL; } @@ -253,6 +326,13 @@ static int kvm_psci_0_1_call(struct kvm_vcpu *vcpu) return 1; } +void kvm_psci_reset(struct kvm_vcpu *vcpu) +{ + vcpu->arch.suspend = false; + vcpu->arch.suspend_entry = 0; + vcpu->arch.suspend_context_id = 0; +} + /** * kvm_psci_call - handle PSCI call if r0 value is in range * @vcpu: Pointer to the VCPU struct diff --git a/arch/arm/kvm/reset.c b/arch/arm/kvm/reset.c index f558c07..220c892 100644 --- a/arch/arm/kvm/reset.c +++ b/arch/arm/kvm/reset.c @@ -26,6 +26,7 @@ #include <asm/cputype.h> #include <asm/kvm_arm.h> #include <asm/kvm_coproc.h> +#include <asm/kvm_psci.h> #include <kvm/arm_arch_timer.h> @@ -79,5 +80,8 @@ int kvm_reset_vcpu(struct kvm_vcpu *vcpu) /* Reset arch_timer context */ kvm_timer_vcpu_reset(vcpu, cpu_vtimer_irq); + /* Reset PSCI state */ + kvm_psci_reset(vcpu); + return 0; } diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h index 92242ce..b2c97dc 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -119,6 +119,11 @@ struct kvm_vcpu_arch { /* Don't run the guest */ bool pause; + /* PSCI suspend state */ + bool suspend; + u64 suspend_entry; + u64 suspend_context_id; + /* IO related fields */ struct kvm_decode mmio_decode; diff --git a/arch/arm64/include/asm/kvm_psci.h b/arch/arm64/include/asm/kvm_psci.h index bc39e55..4da675d 100644 --- a/arch/arm64/include/asm/kvm_psci.h +++ b/arch/arm64/include/asm/kvm_psci.h @@ -22,6 +22,7 @@ #define KVM_ARM_PSCI_0_2 2 int kvm_psci_version(struct kvm_vcpu *vcpu); +void kvm_psci_reset(struct kvm_vcpu *vcpu); int kvm_psci_call(struct kvm_vcpu *vcpu); #endif /* __ARM64_KVM_PSCI_H__ */ diff --git a/arch/arm64/kvm/reset.c b/arch/arm64/kvm/reset.c index 70a7816..aca9f65 100644 --- a/arch/arm64/kvm/reset.c +++ b/arch/arm64/kvm/reset.c @@ -29,6 +29,7 @@ #include <asm/ptrace.h> #include <asm/kvm_arm.h> #include <asm/kvm_coproc.h> +#include <asm/kvm_psci.h> /* * ARMv8 Reset Values @@ -108,5 +109,8 @@ int kvm_reset_vcpu(struct kvm_vcpu *vcpu) /* Reset timer */ kvm_timer_vcpu_reset(vcpu, cpu_vtimer_irq); + /* Reset PSCI state */ + kvm_psci_reset(vcpu); + return 0; } -- 1.7.9.5 _______________________________________________ kvmarm mailing list kvmarm@xxxxxxxxxxxxxxxxxxxxx https://lists.cs.columbia.edu/cucslists/listinfo/kvmarm
