[RFC PATCH 2/5] ARM/ARM64: KVM: Forward PSCI SYSTEM_OFF and SYSTEM_RESET to user space
Anup Patel
anup.patel at linaro.org
Wed Oct 16 13:02:31 EDT 2013
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 at linaro.org>
Signed-off-by: Pranavkumar Sawargaonkar <pranavkumar at 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;
}
/**
--
1.7.9.5
More information about the linux-arm-kernel
mailing list