[PATCH v4 10/10] ARM/ARM64: KVM: Emulate PSCI v0.2 CPU_SUSPEND
Anup Patel
anup.patel at linaro.org
Thu Feb 6 06:31:42 EST 2014
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 at linaro.org>
Signed-off-by: Pranavkumar Sawargaonkar <pranavkumar at linaro.org>
---
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
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