Add "num-breakpoints" and "num-watchpoints" CPU parameters to configure
the debug features that KVM presents to the guest. The KVM vCPU
configuration is modified by calling SET_ONE_REG on the ID register.
This is needed for Realm VMs, whose parameters include breakpoints and
watchpoints, and influence the Realm Initial Measurement.
Signed-off-by: Jean-Philippe Brucker <jean-phili...@linaro.org>
---
v1->v2: new
---
target/arm/cpu.h | 4 ++
target/arm/kvm_arm.h | 2 +
target/arm/arm-qmp-cmds.c | 1 +
target/arm/cpu64.c | 77 +++++++++++++++++++++++++++++++++++++++
target/arm/kvm.c | 56 +++++++++++++++++++++++++++-
5 files changed, 139 insertions(+), 1 deletion(-)
diff --git a/target/arm/cpu.h b/target/arm/cpu.h
index d3ff1b4a31..24080da2b7 100644
--- a/target/arm/cpu.h
+++ b/target/arm/cpu.h
@@ -1089,6 +1089,10 @@ struct ArchCPU {
/* Generic timer counter frequency, in Hz */
uint64_t gt_cntfrq_hz;
+
+ /* Allows to override the default configuration */
+ uint8_t num_bps;
+ uint8_t num_wps;
};
typedef struct ARMCPUInfo {
diff --git a/target/arm/kvm_arm.h b/target/arm/kvm_arm.h
index 4b787dd628..b040686eab 100644
--- a/target/arm/kvm_arm.h
+++ b/target/arm/kvm_arm.h
@@ -16,6 +16,8 @@
#define KVM_ARM_VGIC_V2 (1 << 0)
#define KVM_ARM_VGIC_V3 (1 << 1)
+#define KVM_REG_ARM_ID_AA64DFR0_EL1 ARM64_SYS_REG(3, 0, 0, 5, 0)
+
/**
* kvm_arm_register_device:
* @mr: memory region for this device
diff --git a/target/arm/arm-qmp-cmds.c b/target/arm/arm-qmp-cmds.c
index 3cc8cc738b..0f574bb1dd 100644
--- a/target/arm/arm-qmp-cmds.c
+++ b/target/arm/arm-qmp-cmds.c
@@ -95,6 +95,7 @@ static const char *cpu_model_advertised_features[] = {
"sve1408", "sve1536", "sve1664", "sve1792", "sve1920", "sve2048",
"kvm-no-adjvtime", "kvm-steal-time",
"pauth", "pauth-impdef", "pauth-qarma3",
+ "num-breakpoints", "num-watchpoints",
NULL
};
diff --git a/target/arm/cpu64.c b/target/arm/cpu64.c
index 985b1efe16..9ca74eb019 100644
--- a/target/arm/cpu64.c
+++ b/target/arm/cpu64.c
@@ -571,6 +571,82 @@ void aarch64_add_pauth_properties(Object *obj)
}
}
+#if defined(CONFIG_KVM)
+static void arm_cpu_get_num_wps(Object *obj, Visitor *v, const char *name,
+ void *opaque, Error **errp)
+{
+ uint8_t val;
+ ARMCPU *cpu = ARM_CPU(obj);
+
+ val = cpu->num_wps;
+ if (val == 0) {
+ val = FIELD_EX64(cpu->isar.id_aa64dfr0, ID_AA64DFR0, WRPS) + 1;
+ }
+
+ visit_type_uint8(v, name, &val, errp);
+}
+
+static void arm_cpu_set_num_wps(Object *obj, Visitor *v, const char *name,
+ void *opaque, Error **errp)
+{
+ uint8_t val;
+ ARMCPU *cpu = ARM_CPU(obj);
+ uint8_t max_wps = FIELD_EX64(cpu->isar.id_aa64dfr0, ID_AA64DFR0, WRPS) + 1;
+
+ if (!visit_type_uint8(v, name, &val, errp)) {
+ return;
+ }
+
+ if (val < 2 || val > max_wps) {
+ error_setg(errp, "invalid number of watchpoints");
+ return;
+ }
+
+ cpu->num_wps = val;
+}
+
+static void arm_cpu_get_num_bps(Object *obj, Visitor *v, const char *name,
+ void *opaque, Error **errp)
+{
+ uint8_t val;
+ ARMCPU *cpu = ARM_CPU(obj);
+
+ val = cpu->num_bps;
+ if (val == 0) {
+ val = FIELD_EX64(cpu->isar.id_aa64dfr0, ID_AA64DFR0, BRPS) + 1;
+ }
+
+ visit_type_uint8(v, name, &val, errp);
+}
+
+static void arm_cpu_set_num_bps(Object *obj, Visitor *v, const char *name,
+ void *opaque, Error **errp)
+{
+ uint8_t val;
+ ARMCPU *cpu = ARM_CPU(obj);
+ uint8_t max_bps = FIELD_EX64(cpu->isar.id_aa64dfr0, ID_AA64DFR0, BRPS) + 1;
+
+ if (!visit_type_uint8(v, name, &val, errp)) {
+ return;
+ }
+
+ if (val < 2 || val > max_bps) {
+ error_setg(errp, "invalid number of breakpoints");
+ return;
+ }
+
+ cpu->num_bps = val;
+}
+
+static void aarch64_add_kvm_writable_properties(Object *obj)
+{
+ object_property_add(obj, "num-breakpoints", "uint8", arm_cpu_get_num_bps,
+ arm_cpu_set_num_bps, NULL, NULL);
+ object_property_add(obj, "num-watchpoints", "uint8", arm_cpu_get_num_wps,
+ arm_cpu_set_num_wps, NULL, NULL);
+}
+#endif /* CONFIG_KVM */
+
void arm_cpu_lpa2_finalize(ARMCPU *cpu, Error **errp)
{
uint64_t t;
@@ -713,6 +789,7 @@ static void aarch64_host_initfn(Object *obj)
if (arm_feature(&cpu->env, ARM_FEATURE_AARCH64)) {
aarch64_add_sve_properties(obj);
aarch64_add_pauth_properties(obj);
+ aarch64_add_kvm_writable_properties(obj);
}
#elif defined(CONFIG_HVF)
ARMCPU *cpu = ARM_CPU(obj);
diff --git a/target/arm/kvm.c b/target/arm/kvm.c
index 6d368bf442..623980a25b 100644
--- a/target/arm/kvm.c
+++ b/target/arm/kvm.c
@@ -318,7 +318,7 @@ static bool
kvm_arm_get_host_cpu_features(ARMHostCPUFeatures *ahcf)
err |= read_sys_reg64(fdarray[2], &ahcf->isar.id_aa64smfr0,
ARM64_SYS_REG(3, 0, 0, 4, 5));
err |= read_sys_reg64(fdarray[2], &ahcf->isar.id_aa64dfr0,
- ARM64_SYS_REG(3, 0, 0, 5, 0));
+ KVM_REG_ARM_ID_AA64DFR0_EL1);
err |= read_sys_reg64(fdarray[2], &ahcf->isar.id_aa64dfr1,
ARM64_SYS_REG(3, 0, 0, 5, 1));
err |= read_sys_reg64(fdarray[2], &ahcf->isar.id_aa64isar0,
@@ -876,6 +876,54 @@ out:
return ret;
}
+static void kvm_arm_configure_aa64dfr0(ARMCPU *cpu)
+{
+ int ret;
+ uint64_t val, newval;
+ CPUState *cs = CPU(cpu);
+
+ if (!cpu->num_bps && !cpu->num_wps) {
+ return;
+ }
+
+ newval = cpu->isar.id_aa64dfr0;
+ if (cpu->num_bps) {
+ uint64_t ctx_cmps = FIELD_EX64(newval, ID_AA64DFR0, CTX_CMPS);
+
+ /* CTX_CMPs is never greater than BRPs */
+ ctx_cmps = MIN(ctx_cmps, cpu->num_bps - 1);
+ newval = FIELD_DP64(newval, ID_AA64DFR0, BRPS, cpu->num_bps - 1);
+ newval = FIELD_DP64(newval, ID_AA64DFR0, CTX_CMPS, ctx_cmps);
+ }
+ if (cpu->num_wps) {
+ newval = FIELD_DP64(newval, ID_AA64DFR0, WRPS, cpu->num_wps - 1);
+ }
+ ret = kvm_set_one_reg(cs, KVM_REG_ARM_ID_AA64DFR0_EL1, &newval);
+ if (ret) {
+ error_report("Failed to set KVM_REG_ARM_ID_AA64DFR0_EL1");
+ return;
+ }
+
+ /*
+ * Check if the write succeeded. KVM does offer the writable mask for this
+ * register, but this way we also check if the value we wrote was sane.
+ */
+ ret = kvm_get_one_reg(cs, KVM_REG_ARM_ID_AA64DFR0_EL1, &val);
+ if (ret) {
+ error_report("Failed to get KVM_REG_ARM_ID_AA64DFR0_EL1");
+ return;
+ }
+
+ if (val != newval) {
+ error_report("Failed to update KVM_REG_ARM_ID_AA64DFR0_EL1");
+ }
+}
+
+static void kvm_arm_configure_vcpu_regs(ARMCPU *cpu)
+{
+ kvm_arm_configure_aa64dfr0(cpu);
+}
+
/**
* kvm_arm_cpreg_level:
* @regidx: KVM register index
@@ -995,6 +1043,12 @@ void kvm_arm_reset_vcpu(ARMCPU *cpu)
fprintf(stderr, "kvm_arm_vcpu_init failed: %s\n", strerror(-ret));
abort();
}
+
+ /*
+ * Before loading the KVM values into CPUState, update the KVM
configuration
+ */
+ kvm_arm_configure_vcpu_regs(cpu);
+
if (!write_kvmstate_to_list(cpu)) {
fprintf(stderr, "write_kvmstate_to_list failed\n");
abort();
--
2.44.0
