hw/arm/virt: Implement kvm-steal-time

We add the kvm-steal-time CPU property and implement it for machvirt.
A tiny bit of refactoring was also done to allow pmu and pvtime to
use the same vcpu device helper functions.

Reviewed-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Andrew Jones <drjones@redhat.com>
Message-id: 20201001061718.101915-7-drjones@redhat.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

1 files changed, 59 insertions, 5 deletions

diff --git a/target/arm/kvm64.c b/target/arm/kvm64.c
index fae07c3..f74bac2 100644
--- a/target/arm/kvm64.c
+++ b/target/arm/kvm64.c
@@ -17,6 +17,7 @@
 #include <linux/kvm.h>
 
 #include "qemu-common.h"
+#include "qapi/error.h"
 #include "cpu.h"
 #include "qemu/timer.h"
 #include "qemu/error-report.h"
@@ -397,19 +398,20 @@ static CPUWatchpoint *find_hw_watchpoint(CPUState *cpu, target_ulong addr)
     return NULL;
 }
 
-static bool kvm_arm_pmu_set_attr(CPUState *cs, struct kvm_device_attr *attr)
+static bool kvm_arm_set_device_attr(CPUState *cs, struct kvm_device_attr *attr,
+                                    const char *name)
 {
     int err;
 
     err = kvm_vcpu_ioctl(cs, KVM_HAS_DEVICE_ATTR, attr);
     if (err != 0) {
-        error_report("PMU: KVM_HAS_DEVICE_ATTR: %s", strerror(-err));
+        error_report("%s: KVM_HAS_DEVICE_ATTR: %s", name, strerror(-err));
         return false;
     }
 
     err = kvm_vcpu_ioctl(cs, KVM_SET_DEVICE_ATTR, attr);
     if (err != 0) {
-        error_report("PMU: KVM_SET_DEVICE_ATTR: %s", strerror(-err));
+        error_report("%s: KVM_SET_DEVICE_ATTR: %s", name, strerror(-err));
         return false;
     }
 
@@ -426,7 +428,7 @@ void kvm_arm_pmu_init(CPUState *cs)
     if (!ARM_CPU(cs)->has_pmu) {
         return;
     }
-    if (!kvm_arm_pmu_set_attr(cs, &attr)) {
+    if (!kvm_arm_set_device_attr(cs, &attr, "PMU")) {
         error_report("failed to init PMU");
         abort();
     }
@@ -443,12 +445,29 @@ void kvm_arm_pmu_set_irq(CPUState *cs, int irq)
     if (!ARM_CPU(cs)->has_pmu) {
         return;
     }
-    if (!kvm_arm_pmu_set_attr(cs, &attr)) {
+    if (!kvm_arm_set_device_attr(cs, &attr, "PMU")) {
         error_report("failed to set irq for PMU");
         abort();
     }
 }
 
+void kvm_arm_pvtime_init(CPUState *cs, uint64_t ipa)
+{
+    struct kvm_device_attr attr = {
+        .group = KVM_ARM_VCPU_PVTIME_CTRL,
+        .attr = KVM_ARM_VCPU_PVTIME_IPA,
+        .addr = (uint64_t)&ipa,
+    };
+
+    if (ARM_CPU(cs)->kvm_steal_time == ON_OFF_AUTO_OFF) {
+        return;
+    }
+    if (!kvm_arm_set_device_attr(cs, &attr, "PVTIME IPA")) {
+        error_report("failed to init PVTIME IPA");
+        abort();
+    }
+}
+
 static int read_sys_reg32(int fd, uint32_t *pret, uint64_t id)
 {
     uint64_t ret;
@@ -655,6 +674,36 @@ bool kvm_arm_get_host_cpu_features(ARMHostCPUFeatures *ahcf)
     return true;
 }
 
+void kvm_arm_steal_time_finalize(ARMCPU *cpu, Error **errp)
+{
+    bool has_steal_time = kvm_arm_steal_time_supported();
+
+    if (cpu->kvm_steal_time == ON_OFF_AUTO_AUTO) {
+        if (!has_steal_time || !arm_feature(&cpu->env, ARM_FEATURE_AARCH64)) {
+            cpu->kvm_steal_time = ON_OFF_AUTO_OFF;
+        } else {
+            cpu->kvm_steal_time = ON_OFF_AUTO_ON;
+        }
+    } else if (cpu->kvm_steal_time == ON_OFF_AUTO_ON) {
+        if (!has_steal_time) {
+            error_setg(errp, "'kvm-steal-time' cannot be enabled "
+                             "on this host");
+            return;
+        } else if (!arm_feature(&cpu->env, ARM_FEATURE_AARCH64)) {
+            /*
+             * DEN0057A chapter 2 says "This specification only covers
+             * systems in which the Execution state of the hypervisor
+             * as well as EL1 of virtual machines is AArch64.". And,
+             * to ensure that, the smc/hvc calls are only specified as
+             * smc64/hvc64.
+             */
+            error_setg(errp, "'kvm-steal-time' cannot be enabled "
+                             "for AArch32 guests");
+            return;
+        }
+    }
+}
+
 bool kvm_arm_aarch32_supported(void)
 {
     return kvm_check_extension(kvm_state, KVM_CAP_ARM_EL1_32BIT);
@@ -665,6 +714,11 @@ bool kvm_arm_sve_supported(void)
     return kvm_check_extension(kvm_state, KVM_CAP_ARM_SVE);
 }
 
+bool kvm_arm_steal_time_supported(void)
+{
+    return kvm_check_extension(kvm_state, KVM_CAP_STEAL_TIME);
+}
+
 QEMU_BUILD_BUG_ON(KVM_ARM64_SVE_VQ_MIN != 1);
 
 void kvm_arm_sve_get_vls(CPUState *cs, unsigned long *map)