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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [PATCH v6 1/4] xen/arm: Implement PSCI SYSTEM_SUSPEND call for guests
From: Mykola Kvach <mykola_kvach@xxxxxxxx>
This patch adds support for the PSCI SYSTEM_SUSPEND function in the vPSCI
(virtual PSCI) interface, allowing guests to request suspend via the PSCI
v1.0 SYSTEM_SUSPEND call (both 32-bit and 64-bit variants).
The implementation:
- Adds SYSTEM_SUSPEND function IDs to PSCI definitions
- Implements trapping and handling of SYSTEM_SUSPEND in vPSCI
- Allows only non-hardware domains to invoke SYSTEM_SUSPEND; for the
hardware domain, PSCI_NOT_SUPPORTED is returned to avoid halting the
system in hwdom_shutdown() called from domain_shutdown
- Ensures all secondary VCPUs of the calling domain are offline before
allowing suspend due to PSCI spec
Usage:
For Linux-based guests, suspend can be initiated with:
echo mem > /sys/power/state
or via:
systemctl suspend
Resuming the guest is performed from control domain using:
xl resume <domain>
Signed-off-by: Mykola Kvach <mykola_kvach@xxxxxxxx>
---
Changes in V6:
- skip execution of ctxt_switch_from for vcpu that is in paused domain
- add implementation of domain_resume without domain_pause
- add helper function to determine if vcpu is suspended or not
- ignore upper 32 bits of argument values when the domain is 64-bit
and calls the SMC32 SYSTEM_SUSPEND function
- cosmetic changes after review
Changes in V5:
- don't use standby mode, restore execution in a provided by guest point
- move checking that all CPUs, except current one, are offline to after
pausing the vCPUs
- provide ret status from arch_domain_shutdown and handle it in
domain_shutdown
- adjust VPSCI_NR_FUNCS to reflect the number of newly added PSCI functions
Changes in V4:
Dropped all changes related to watchdog, domain is marked as shutting
down in domain_shutdown and watchdog timeout handler won't trigger
because of it.
Previous versions included code to manage Xen watchdog timers during suspend,
but this was removed. When a guest OS starts the Xen watchdog (either via the
kernel driver or xenwatchdogd), it is responsible for managing that state
across suspend/resume. On Linux, the Xen kernel driver properly stops the
watchdog during suspend. However, when xenwatchdogd is used instead, suspend
handling is incomplete, potentially leading to watchdog-triggered resets on
resume. Xen leaves watchdog handling to the guest OS and its services.
Dropped all changes related to VCPU context, because instead domain_shutdown
is used, so we don't need any extra changes for suspending domain.
Changes in V3:
Dropped all domain flags and related code (which touched common functions like
vcpu_unblock), keeping only the necessary changes for Xen suspend/resume, i.e.
suspend/resume is now fully supported only for the hardware domain.
Proper support for domU suspend/resume will be added in a future patch.
This patch does not yet include VCPU context reset or domain context
restoration in VCPU.
---
xen/arch/arm/domain.c | 4 ++
xen/arch/arm/include/asm/perfc_defn.h | 1 +
xen/arch/arm/include/asm/psci.h | 2 +
xen/arch/arm/include/asm/vpsci.h | 2 +-
xen/arch/arm/vpsci.c | 90 +++++++++++++++++++++++----
xen/common/domain.c | 30 ++++++---
xen/include/xen/sched.h | 2 +
7 files changed, 110 insertions(+), 21 deletions(-)
diff --git a/xen/arch/arm/domain.c b/xen/arch/arm/domain.c
index 79a144e61b..a2ad10146f 100644
--- a/xen/arch/arm/domain.c
+++ b/xen/arch/arm/domain.c
@@ -90,6 +90,10 @@ static void ctxt_switch_from(struct vcpu *p)
if ( is_idle_vcpu(p) )
return;
+ /* VCPU's context should not be saved if its domain is suspended */
+ if ( vcpu_is_suspended(p) )
+ return;
+
p2m_save_state(p);
/* CP 15 */
diff --git a/xen/arch/arm/include/asm/perfc_defn.h
b/xen/arch/arm/include/asm/perfc_defn.h
index effd25b69e..8dfcac7e3b 100644
--- a/xen/arch/arm/include/asm/perfc_defn.h
+++ b/xen/arch/arm/include/asm/perfc_defn.h
@@ -33,6 +33,7 @@ PERFCOUNTER(vpsci_system_reset, "vpsci: system_reset")
PERFCOUNTER(vpsci_cpu_suspend, "vpsci: cpu_suspend")
PERFCOUNTER(vpsci_cpu_affinity_info, "vpsci: cpu_affinity_info")
PERFCOUNTER(vpsci_features, "vpsci: features")
+PERFCOUNTER(vpsci_system_suspend, "vpsci: system_suspend")
PERFCOUNTER(vcpu_kick, "vcpu: notify other vcpu")
diff --git a/xen/arch/arm/include/asm/psci.h b/xen/arch/arm/include/asm/psci.h
index 4780972621..48a93e6b79 100644
--- a/xen/arch/arm/include/asm/psci.h
+++ b/xen/arch/arm/include/asm/psci.h
@@ -47,10 +47,12 @@ void call_psci_system_reset(void);
#define PSCI_0_2_FN32_SYSTEM_OFF PSCI_0_2_FN32(8)
#define PSCI_0_2_FN32_SYSTEM_RESET PSCI_0_2_FN32(9)
#define PSCI_1_0_FN32_PSCI_FEATURES PSCI_0_2_FN32(10)
+#define PSCI_1_0_FN32_SYSTEM_SUSPEND PSCI_0_2_FN32(14)
#define PSCI_0_2_FN64_CPU_SUSPEND PSCI_0_2_FN64(1)
#define PSCI_0_2_FN64_CPU_ON PSCI_0_2_FN64(3)
#define PSCI_0_2_FN64_AFFINITY_INFO PSCI_0_2_FN64(4)
+#define PSCI_1_0_FN64_SYSTEM_SUSPEND PSCI_0_2_FN64(14)
/* PSCI v0.2 affinity level state returned by AFFINITY_INFO */
#define PSCI_0_2_AFFINITY_LEVEL_ON 0
diff --git a/xen/arch/arm/include/asm/vpsci.h b/xen/arch/arm/include/asm/vpsci.h
index 0cca5e6830..69d40f9d7f 100644
--- a/xen/arch/arm/include/asm/vpsci.h
+++ b/xen/arch/arm/include/asm/vpsci.h
@@ -23,7 +23,7 @@
#include <asm/psci.h>
/* Number of function implemented by virtual PSCI (only 0.2 or later) */
-#define VPSCI_NR_FUNCS 12
+#define VPSCI_NR_FUNCS 14
/* Functions handle PSCI calls from the guests */
bool do_vpsci_0_1_call(struct cpu_user_regs *regs, uint32_t fid);
diff --git a/xen/arch/arm/vpsci.c b/xen/arch/arm/vpsci.c
index 7ba9ccd94b..11334b3426 100644
--- a/xen/arch/arm/vpsci.c
+++ b/xen/arch/arm/vpsci.c
@@ -10,28 +10,18 @@
#include <public/sched.h>
-static int do_common_cpu_on(register_t target_cpu, register_t entry_point,
+static int do_setup_vcpu_ctx(struct vcpu *v, register_t entry_point,
register_t context_id)
{
- struct vcpu *v;
struct domain *d = current->domain;
struct vcpu_guest_context *ctxt;
int rc;
bool is_thumb = entry_point & 1;
- register_t vcpuid;
-
- vcpuid = vaffinity_to_vcpuid(target_cpu);
-
- if ( (v = domain_vcpu(d, vcpuid)) == NULL )
- return PSCI_INVALID_PARAMETERS;
/* THUMB set is not allowed with 64-bit domain */
if ( is_64bit_domain(d) && is_thumb )
return PSCI_INVALID_ADDRESS;
- if ( !test_bit(_VPF_down, &v->pause_flags) )
- return PSCI_ALREADY_ON;
-
if ( (ctxt = alloc_vcpu_guest_context()) == NULL )
return PSCI_DENIED;
@@ -78,11 +68,32 @@ static int do_common_cpu_on(register_t target_cpu,
register_t entry_point,
if ( rc < 0 )
return PSCI_DENIED;
- vcpu_wake(v);
-
return PSCI_SUCCESS;
}
+static int do_common_cpu_on(register_t target_cpu, register_t entry_point,
+ register_t context_id)
+{
+ int rc;
+ struct vcpu *v;
+ struct domain *d = current->domain;
+ register_t vcpuid;
+
+ vcpuid = vaffinity_to_vcpuid(target_cpu);
+
+ if ( (v = domain_vcpu(d, vcpuid)) == NULL )
+ return PSCI_INVALID_PARAMETERS;
+
+ if ( !test_bit(_VPF_down, &v->pause_flags) )
+ return PSCI_ALREADY_ON;
+
+ rc = do_setup_vcpu_ctx(v, entry_point, context_id);
+ if ( rc == PSCI_SUCCESS )
+ vcpu_wake(v);
+
+ return rc;
+}
+
static int32_t do_psci_cpu_on(uint32_t vcpuid, register_t entry_point)
{
int32_t ret;
@@ -197,6 +208,39 @@ static void do_psci_0_2_system_reset(void)
domain_shutdown(d,SHUTDOWN_reboot);
}
+static int32_t do_psci_1_0_system_suspend(register_t epoint, register_t cid)
+{
+ int ret;
+ struct vcpu *v;
+ struct domain *d = current->domain;
+
+ /* SYSTEM_SUSPEND is not supported for the hardware domain yet */
+ if ( is_hardware_domain(d) )
+ return PSCI_NOT_SUPPORTED;
+
+ /*
+ * Shut down the domain first to ensure all vCPUs are paused
+ * before checking that they (except the calling one) are offline.
+ */
+ domain_shutdown(d, SHUTDOWN_suspend);
+
+ /* Ensure that all CPUs other than the calling one are offline */
+ for_each_vcpu ( d, v )
+ {
+ if ( v != current && is_vcpu_online(v) )
+ {
+ domain_resume_nopause(d);
+ return PSCI_DENIED;
+ }
+ }
+
+ ret = do_setup_vcpu_ctx(current, epoint, cid);
+ if ( ret != PSCI_SUCCESS )
+ domain_resume_nopause(d);
+
+ return ret;
+}
+
static int32_t do_psci_1_0_features(uint32_t psci_func_id)
{
/* /!\ Ordered by function ID and not name */
@@ -214,6 +258,8 @@ static int32_t do_psci_1_0_features(uint32_t psci_func_id)
case PSCI_0_2_FN32_SYSTEM_OFF:
case PSCI_0_2_FN32_SYSTEM_RESET:
case PSCI_1_0_FN32_PSCI_FEATURES:
+ case PSCI_1_0_FN32_SYSTEM_SUSPEND:
+ case PSCI_1_0_FN64_SYSTEM_SUSPEND:
case ARM_SMCCC_VERSION_FID:
return 0;
default:
@@ -344,6 +390,24 @@ bool do_vpsci_0_2_call(struct cpu_user_regs *regs,
uint32_t fid)
return true;
}
+ case PSCI_1_0_FN32_SYSTEM_SUSPEND:
+ case PSCI_1_0_FN64_SYSTEM_SUSPEND:
+ {
+ register_t epoint = PSCI_ARG(regs, 1);
+ register_t cid = PSCI_ARG(regs, 2);
+
+ if ( is_64bit_domain(current->domain) &&
+ fid == PSCI_1_0_FN32_SYSTEM_SUSPEND )
+ {
+ epoint &= GENMASK(31, 0);
+ cid &= GENMASK(31, 0);
+ }
+
+ perfc_incr(vpsci_system_suspend);
+ PSCI_SET_RESULT(regs, do_psci_1_0_system_suspend(epoint, cid));
+ return true;
+ }
+
default:
return false;
}
diff --git a/xen/common/domain.c b/xen/common/domain.c
index 303c338ef2..5b760f0cd9 100644
--- a/xen/common/domain.c
+++ b/xen/common/domain.c
@@ -1326,16 +1326,10 @@ int domain_shutdown(struct domain *d, u8 reason)
return 0;
}
-void domain_resume(struct domain *d)
+void domain_resume_nopause(struct domain *d)
{
struct vcpu *v;
- /*
- * Some code paths assume that shutdown status does not get reset under
- * their feet (e.g., some assertions make this assumption).
- */
- domain_pause(d);
-
spin_lock(&d->shutdown_lock);
d->is_shutting_down = d->is_shut_down = 0;
@@ -1349,10 +1343,32 @@ void domain_resume(struct domain *d)
}
spin_unlock(&d->shutdown_lock);
+}
+void domain_resume(struct domain *d)
+{
+ /*
+ * Some code paths assume that shutdown status does not get reset under
+ * their feet (e.g., some assertions make this assumption).
+ */
+ domain_pause(d);
+ domain_resume_nopause(d);
domain_unpause(d);
}
+bool vcpu_is_suspended(struct vcpu *v)
+{
+ bool is_suspended;
+ struct domain *d = v->domain;
+
+ spin_lock(&d->shutdown_lock);
+ is_suspended = d->shutdown_code == SHUTDOWN_suspend &&
+ v->paused_for_shutdown;
+ spin_unlock(&d->shutdown_lock);
+
+ return is_suspended;
+}
+
int vcpu_start_shutdown_deferral(struct vcpu *v)
{
if ( v->defer_shutdown )
diff --git a/xen/include/xen/sched.h b/xen/include/xen/sched.h
index fe53d4fab7..2e163497bd 100644
--- a/xen/include/xen/sched.h
+++ b/xen/include/xen/sched.h
@@ -814,6 +814,7 @@ void domain_destroy(struct domain *d);
int domain_kill(struct domain *d);
int domain_shutdown(struct domain *d, u8 reason);
void domain_resume(struct domain *d);
+void domain_resume_nopause(struct domain *d);
int domain_soft_reset(struct domain *d, bool resuming);
@@ -824,6 +825,7 @@ int get_domain_state(struct xen_domctl_get_domain_state
*info,
int vcpu_start_shutdown_deferral(struct vcpu *v);
void vcpu_end_shutdown_deferral(struct vcpu *v);
+bool vcpu_is_suspended(struct vcpu *v);
/*
* Mark specified domain as crashed. This function always returns, even if the
--
2.48.1
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