The PSCI SYSTEM_OFF and SYSTEM_RESET functions are VM or Guest level functions hence cannot be emulated by the in-kernel PSCI emulation code.
To tackle this, we forward PSCI SYSTEM_OFF and SYSTEM_RESET function calls from Guest to user space (i.e. QEMU or KVMTOOL) via KVM run structure with KVM_EXIT_PSCI exit reason.
Signed-off-by: Anup Patel anup.patel@linaro.org Signed-off-by: Pranavkumar Sawargaonkar pranavkumar@linaro.org --- arch/arm/include/asm/kvm_psci.h | 25 +++++++++++++++- arch/arm/include/uapi/asm/kvm.h | 2 ++ arch/arm/kvm/arm.c | 12 ++++++-- arch/arm/kvm/handle_exit.c | 12 ++++++-- arch/arm/kvm/psci.c | 57 ++++++++++++++++++++++++++++++++++--- arch/arm64/include/asm/kvm_psci.h | 25 +++++++++++++++- arch/arm64/include/uapi/asm/kvm.h | 2 ++ arch/arm64/kvm/handle_exit.c | 24 ++++++++++++---- 8 files changed, 141 insertions(+), 18 deletions(-)
diff --git a/arch/arm/include/asm/kvm_psci.h b/arch/arm/include/asm/kvm_psci.h index 9a83d98..783566f 100644 --- a/arch/arm/include/asm/kvm_psci.h +++ b/arch/arm/include/asm/kvm_psci.h @@ -18,6 +18,29 @@ #ifndef __ARM_KVM_PSCI_H__ #define __ARM_KVM_PSCI_H__
-bool kvm_psci_call(struct kvm_vcpu *vcpu); +#include <linux/kvm_host.h> +#include <asm/kvm_asm.h> +#include <asm/kvm_arm.h> + +/* + * The in-kernel PSCI emulation code wants to use a copy of run->psci, + * which is an anonymous type. Use our own type instead. + */ +struct kvm_exit_psci { + u32 fn; + u64 args[7]; +}; + +static inline void kvm_prepare_psci(struct kvm_run *run, + struct kvm_exit_psci *psci) +{ + run->psci.fn = psci->fn; + memcpy(&run->psci.args, &psci->args, sizeof(run->psci.args)); + memset(&run->psci.ret, 0, sizeof(run->psci.ret)); + run->exit_reason = KVM_EXIT_PSCI; +} + +int kvm_handle_psci_return(struct kvm_vcpu *vcpu, struct kvm_run *run); +int kvm_psci_call(struct kvm_vcpu *vcpu, struct kvm_run *run);
#endif /* __ARM_KVM_PSCI_H__ */ diff --git a/arch/arm/include/uapi/asm/kvm.h b/arch/arm/include/uapi/asm/kvm.h index c1ee007..205cf0e 100644 --- a/arch/arm/include/uapi/asm/kvm.h +++ b/arch/arm/include/uapi/asm/kvm.h @@ -171,6 +171,8 @@ struct kvm_arch_memory_slot { #define KVM_PSCI_FN_CPU_OFF KVM_PSCI_FN(1) #define KVM_PSCI_FN_CPU_ON KVM_PSCI_FN(2) #define KVM_PSCI_FN_MIGRATE KVM_PSCI_FN(3) +#define KVM_PSCI_FN_SYSTEM_OFF KVM_PSCI_FN(4) +#define KVM_PSCI_FN_SYSTEM_RESET KVM_PSCI_FN(5)
#define KVM_PSCI_RET_SUCCESS 0 #define KVM_PSCI_RET_NI ((unsigned long)-1) diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c index cc5adb9..5ffd9a3 100644 --- a/arch/arm/kvm/arm.c +++ b/arch/arm/kvm/arm.c @@ -459,7 +459,7 @@ static void update_vttbr(struct kvm *kvm) spin_unlock(&kvm_vmid_lock); }
-static int kvm_vcpu_first_run_init(struct kvm_vcpu *vcpu) +static int kvm_vcpu_first_run_init(struct kvm_vcpu *vcpu, struct kvm_run *run) { if (likely(vcpu->arch.has_run_once)) return 0; @@ -483,7 +483,7 @@ static int kvm_vcpu_first_run_init(struct kvm_vcpu *vcpu) */ if (test_and_clear_bit(KVM_ARM_VCPU_POWER_OFF, vcpu->arch.features)) { *vcpu_reg(vcpu, 0) = KVM_PSCI_FN_CPU_OFF; - kvm_psci_call(vcpu); + kvm_psci_call(vcpu, run); }
return 0; @@ -520,7 +520,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run) if (unlikely(!kvm_vcpu_initialized(vcpu))) return -ENOEXEC;
- ret = kvm_vcpu_first_run_init(vcpu); + ret = kvm_vcpu_first_run_init(vcpu, vcpu->run); if (ret) return ret;
@@ -530,6 +530,12 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run) return ret; }
+ if (run->exit_reason == KVM_EXIT_PSCI) { + ret = kvm_handle_psci_return(vcpu, vcpu->run); + if (ret) + return ret; + } + if (vcpu->sigset_active) sigprocmask(SIG_SETMASK, &vcpu->sigset, &sigsaved);
diff --git a/arch/arm/kvm/handle_exit.c b/arch/arm/kvm/handle_exit.c index df4c82d..1a12e6c 100644 --- a/arch/arm/kvm/handle_exit.c +++ b/arch/arm/kvm/handle_exit.c @@ -40,14 +40,20 @@ static int handle_svc_hyp(struct kvm_vcpu *vcpu, struct kvm_run *run)
static int handle_hvc(struct kvm_vcpu *vcpu, struct kvm_run *run) { + int ret; + trace_kvm_hvc(*vcpu_pc(vcpu), *vcpu_reg(vcpu, 0), kvm_vcpu_hvc_get_imm(vcpu));
- if (kvm_psci_call(vcpu)) + ret = kvm_psci_call(vcpu, run); + if (!ret) + return 1; + else if (ret == -EINVAL) { + kvm_inject_undefined(vcpu); return 1; + }
- kvm_inject_undefined(vcpu); - return 1; + return 0; }
static int handle_smc(struct kvm_vcpu *vcpu, struct kvm_run *run) diff --git a/arch/arm/kvm/psci.c b/arch/arm/kvm/psci.c index 86a693a..72c23a7 100644 --- a/arch/arm/kvm/psci.c +++ b/arch/arm/kvm/psci.c @@ -71,6 +71,45 @@ static unsigned long kvm_psci_vcpu_on(struct kvm_vcpu *source_vcpu) return KVM_PSCI_RET_SUCCESS; }
+static void kvm_psci_system_off(struct kvm_vcpu *vcpu, struct kvm_run *run) +{ + struct kvm_exit_psci psci; + + psci.fn = KVM_PSCI_FN_SYSTEM_OFF; + memset(&psci.args, 0, sizeof(psci.args)); + kvm_prepare_psci(run, &psci); +} + +static void kvm_psci_system_reset(struct kvm_vcpu *vcpu, struct kvm_run *run) +{ + struct kvm_exit_psci psci; + + psci.fn = KVM_PSCI_FN_SYSTEM_RESET; + memset(&psci.args, 0, sizeof(psci.args)); + kvm_prepare_psci(run, &psci); +} + +/** + * kvm_handle_psci_return -- Handle PSCI after user space emulation + * @vcpu: The VCPU pointer + * @run: The VCPU run struct containing the psci data + * + * This should only be called after returning from userspace for + * PSCI emulation. + */ +int kvm_handle_psci_return(struct kvm_vcpu *vcpu, struct kvm_run *run) +{ + /* + * Currently, the PSCI functions passed to user space for emulation + * are SYSTEM_OFF and SYSTEM_RESET. These PSCI functions are not + * expected to return back after emulating in user space hence by + * default we return -EINVAL to avoid user space from doing RUN ioctl + * after handling KVM_EXIT_PSCI. + */ + + return -EINVAL; +} + /** * kvm_psci_call - handle PSCI call if r0 value is in range * @vcpu: Pointer to the VCPU struct @@ -81,8 +120,9 @@ static unsigned long kvm_psci_vcpu_on(struct kvm_vcpu *source_vcpu) * function number specified in r0 is withing the PSCI range, and false * otherwise. */ -bool kvm_psci_call(struct kvm_vcpu *vcpu) +int kvm_psci_call(struct kvm_vcpu *vcpu, struct kvm_run *run) { + int ret = 0; unsigned long psci_fn = *vcpu_reg(vcpu, 0) & ~((u32) 0); unsigned long val;
@@ -98,11 +138,20 @@ bool kvm_psci_call(struct kvm_vcpu *vcpu) case KVM_PSCI_FN_MIGRATE: val = KVM_PSCI_RET_NI; break; - + case KVM_PSCI_FN_SYSTEM_OFF: + kvm_psci_system_off(vcpu, run); + val = KVM_PSCI_RET_SUCCESS; + ret = -EINTR; + break; + case KVM_PSCI_FN_SYSTEM_RESET: + kvm_psci_system_reset(vcpu, run); + val = KVM_PSCI_RET_SUCCESS; + ret = -EINTR; + break; default: - return false; + return -EINVAL; }
*vcpu_reg(vcpu, 0) = val; - return true; + return ret; } diff --git a/arch/arm64/include/asm/kvm_psci.h b/arch/arm64/include/asm/kvm_psci.h index e301a48..db90649 100644 --- a/arch/arm64/include/asm/kvm_psci.h +++ b/arch/arm64/include/asm/kvm_psci.h @@ -18,6 +18,29 @@ #ifndef __ARM64_KVM_PSCI_H__ #define __ARM64_KVM_PSCI_H__
-bool kvm_psci_call(struct kvm_vcpu *vcpu); +#include <linux/kvm_host.h> +#include <asm/kvm_asm.h> +#include <asm/kvm_arm.h> + +/* + * The in-kernel PSCI emulation code wants to use a copy of run->psci, + * which is an anonymous type. Use our own type instead. + */ +struct kvm_exit_psci { + u32 fn; + u64 args[7]; +}; + +static inline void kvm_prepare_psci(struct kvm_run *run, + struct kvm_exit_psci *psci) +{ + run->psci.fn = psci->fn; + memcpy(&run->psci.args, &psci->args, sizeof(run->psci.args)); + memset(&run->psci.ret, 0, sizeof(run->psci.ret)); + run->exit_reason = KVM_EXIT_PSCI; +} + +int kvm_handle_psci_return(struct kvm_vcpu *vcpu, struct kvm_run *run); +int kvm_psci_call(struct kvm_vcpu *vcpu, struct kvm_run *run);
#endif /* __ARM64_KVM_PSCI_H__ */ diff --git a/arch/arm64/include/uapi/asm/kvm.h b/arch/arm64/include/uapi/asm/kvm.h index d9f026b..f678902 100644 --- a/arch/arm64/include/uapi/asm/kvm.h +++ b/arch/arm64/include/uapi/asm/kvm.h @@ -158,6 +158,8 @@ struct kvm_arch_memory_slot { #define KVM_PSCI_FN_CPU_OFF KVM_PSCI_FN(1) #define KVM_PSCI_FN_CPU_ON KVM_PSCI_FN(2) #define KVM_PSCI_FN_MIGRATE KVM_PSCI_FN(3) +#define KVM_PSCI_FN_SYSTEM_OFF KVM_PSCI_FN(4) +#define KVM_PSCI_FN_SYSTEM_RESET KVM_PSCI_FN(5)
#define KVM_PSCI_RET_SUCCESS 0 #define KVM_PSCI_RET_NI ((unsigned long)-1) diff --git a/arch/arm64/kvm/handle_exit.c b/arch/arm64/kvm/handle_exit.c index 9beaca0..28e20bb 100644 --- a/arch/arm64/kvm/handle_exit.c +++ b/arch/arm64/kvm/handle_exit.c @@ -30,20 +30,32 @@ typedef int (*exit_handle_fn)(struct kvm_vcpu *, struct kvm_run *);
static int handle_hvc(struct kvm_vcpu *vcpu, struct kvm_run *run) { - if (kvm_psci_call(vcpu)) + int ret; + + ret = kvm_psci_call(vcpu, run); + if (!ret) + return 1; + else if (ret == -EINVAL) { + kvm_inject_undefined(vcpu); return 1; + }
- kvm_inject_undefined(vcpu); - return 1; + return 0; }
static int handle_smc(struct kvm_vcpu *vcpu, struct kvm_run *run) { - if (kvm_psci_call(vcpu)) + int ret; + + ret = kvm_psci_call(vcpu, run); + if (!ret) + return 1; + else if (ret == -EINVAL) { + kvm_inject_undefined(vcpu); return 1; + }
- kvm_inject_undefined(vcpu); - return 1; + return 0; }
/**