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-rw-r--r--arch/arm64/kernel/paravirt.c140
1 files changed, 140 insertions, 0 deletions
diff --git a/arch/arm64/kernel/paravirt.c b/arch/arm64/kernel/paravirt.c
index 4cfed91fe256..1ef702b0be2d 100644
--- a/arch/arm64/kernel/paravirt.c
+++ b/arch/arm64/kernel/paravirt.c
@@ -6,13 +6,153 @@
* Author: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
*/
+#define pr_fmt(fmt) "arm-pv: " fmt
+
+#include <linux/arm-smccc.h>
+#include <linux/cpuhotplug.h>
#include <linux/export.h>
+#include <linux/io.h>
#include <linux/jump_label.h>
+#include <linux/printk.h>
+#include <linux/psci.h>
+#include <linux/reboot.h>
+#include <linux/slab.h>
#include <linux/types.h>
+
#include <asm/paravirt.h>
+#include <asm/pvclock-abi.h>
+#include <asm/smp_plat.h>
struct static_key paravirt_steal_enabled;
struct static_key paravirt_steal_rq_enabled;
struct paravirt_patch_template pv_ops;
EXPORT_SYMBOL_GPL(pv_ops);
+
+struct pv_time_stolen_time_region {
+ struct pvclock_vcpu_stolen_time *kaddr;
+};
+
+static DEFINE_PER_CPU(struct pv_time_stolen_time_region, stolen_time_region);
+
+static bool steal_acc = true;
+static int __init parse_no_stealacc(char *arg)
+{
+ steal_acc = false;
+ return 0;
+}
+
+early_param("no-steal-acc", parse_no_stealacc);
+
+/* return stolen time in ns by asking the hypervisor */
+static u64 pv_steal_clock(int cpu)
+{
+ struct pv_time_stolen_time_region *reg;
+
+ reg = per_cpu_ptr(&stolen_time_region, cpu);
+ if (!reg->kaddr) {
+ pr_warn_once("stolen time enabled but not configured for cpu %d\n",
+ cpu);
+ return 0;
+ }
+
+ return le64_to_cpu(READ_ONCE(reg->kaddr->stolen_time));
+}
+
+static int stolen_time_dying_cpu(unsigned int cpu)
+{
+ struct pv_time_stolen_time_region *reg;
+
+ reg = this_cpu_ptr(&stolen_time_region);
+ if (!reg->kaddr)
+ return 0;
+
+ memunmap(reg->kaddr);
+ memset(reg, 0, sizeof(*reg));
+
+ return 0;
+}
+
+static int init_stolen_time_cpu(unsigned int cpu)
+{
+ struct pv_time_stolen_time_region *reg;
+ struct arm_smccc_res res;
+
+ reg = this_cpu_ptr(&stolen_time_region);
+
+ arm_smccc_1_1_invoke(ARM_SMCCC_HV_PV_TIME_ST, &res);
+
+ if (res.a0 == SMCCC_RET_NOT_SUPPORTED)
+ return -EINVAL;
+
+ reg->kaddr = memremap(res.a0,
+ sizeof(struct pvclock_vcpu_stolen_time),
+ MEMREMAP_WB);
+
+ if (!reg->kaddr) {
+ pr_warn("Failed to map stolen time data structure\n");
+ return -ENOMEM;
+ }
+
+ if (le32_to_cpu(reg->kaddr->revision) != 0 ||
+ le32_to_cpu(reg->kaddr->attributes) != 0) {
+ pr_warn_once("Unexpected revision or attributes in stolen time data\n");
+ return -ENXIO;
+ }
+
+ return 0;
+}
+
+static int pv_time_init_stolen_time(void)
+{
+ int ret;
+
+ ret = cpuhp_setup_state(CPUHP_AP_ARM_KVMPV_STARTING,
+ "hypervisor/arm/pvtime:starting",
+ init_stolen_time_cpu, stolen_time_dying_cpu);
+ if (ret < 0)
+ return ret;
+ return 0;
+}
+
+static bool has_pv_steal_clock(void)
+{
+ struct arm_smccc_res res;
+
+ /* To detect the presence of PV time support we require SMCCC 1.1+ */
+ if (psci_ops.smccc_version < SMCCC_VERSION_1_1)
+ return false;
+
+ arm_smccc_1_1_invoke(ARM_SMCCC_ARCH_FEATURES_FUNC_ID,
+ ARM_SMCCC_HV_PV_TIME_FEATURES, &res);
+
+ if (res.a0 != SMCCC_RET_SUCCESS)
+ return false;
+
+ arm_smccc_1_1_invoke(ARM_SMCCC_HV_PV_TIME_FEATURES,
+ ARM_SMCCC_HV_PV_TIME_ST, &res);
+
+ return (res.a0 == SMCCC_RET_SUCCESS);
+}
+
+int __init pv_time_init(void)
+{
+ int ret;
+
+ if (!has_pv_steal_clock())
+ return 0;
+
+ ret = pv_time_init_stolen_time();
+ if (ret)
+ return ret;
+
+ pv_ops.time.steal_clock = pv_steal_clock;
+
+ static_key_slow_inc(&paravirt_steal_enabled);
+ if (steal_acc)
+ static_key_slow_inc(&paravirt_steal_rq_enabled);
+
+ pr_info("using stolen time PV\n");
+
+ return 0;
+}