From: Eric Auger <eric.au...@redhat.com>
If the interface for writable ID registers is available, expose uint64
SYSREG properties for writable ID reg fields exposed by the host
kernel. Properties are named SYSREG_<REG>_<FIELD> with REG and FIELD
being those used in linux arch/arm64/tools/sysreg. This done by
matching the writable fields retrieved from the host kernel against the
generated description of sysregs.
An example of invocation is:
-cpu host,SYSREG_ID_AA64ISAR0_EL1_DP=0x0
which sets DP field of ID_AA64ISAR0_EL1 to 0.
[CH: add properties to the host model instead of introducing a new
"custom" model]
Signed-off-by: Eric Auger <eric.au...@redhat.com>
Signed-off-by: Cornelia Huck <coh...@redhat.com>
---
Interaction with the existing cpu properties is still a bit unclear --
at the moment, the different configurations can overwrite each other.
---
target/arm/cpu.c | 12 ++++
target/arm/cpu64.c | 22 ++++++-
target/arm/kvm.c | 135 ++++++++++++++++++++++++++++++++++++++++
target/arm/kvm_arm.h | 10 +++
target/arm/trace-events | 4 ++
5 files changed, 182 insertions(+), 1 deletion(-)
diff --git a/target/arm/cpu.c b/target/arm/cpu.c
index a3de5ee2b19c..c03f38ad5cfe 100644
--- a/target/arm/cpu.c
+++ b/target/arm/cpu.c
@@ -1991,6 +1991,18 @@ static void arm_cpu_realizefn(DeviceState *dev, Error
**errp)
return;
}
+ /*
+ * If we failed to retrieve the set of writable ID registers for the "host"
+ * CPU model, report it here. No error if the interface for discovering
+ * writable ID registers is not available.
+ * In case we did get the set of writable ID registers, set the features to
+ * the configured values here and perform some sanity checks.
+ */
+ if (cpu->writable_id_regs == WRITABLE_ID_REGS_FAILED) {
+ error_setg(errp, "Failed to discover writable id registers");
+ return;
+ }
+
if (!cpu->gt_cntfrq_hz) {
/*
* 0 means "the board didn't set a value, use the default". (We also
diff --git a/target/arm/cpu64.c b/target/arm/cpu64.c
index 60a709502697..c595dbb532c1 100644
--- a/target/arm/cpu64.c
+++ b/target/arm/cpu64.c
@@ -757,11 +757,31 @@ static void aarch64_host_initfn(Object *obj)
{
#if defined(CONFIG_KVM)
ARMCPU *cpu = ARM_CPU(obj);
- kvm_arm_set_cpu_features_from_host(cpu, false);
+ bool expose_id_regs = true;
+ int ret;
+
+ cpu->writable_map = g_malloc(sizeof(IdRegMap));
+
+ /* discover via KVM_ARM_GET_REG_WRITABLE_MASKS */
+ ret = kvm_arm_get_writable_id_regs(cpu, cpu->writable_map);
+ if (ret == -ENOSYS) {
+ /* legacy: continue without writable id regs */
+ expose_id_regs = false;
+ } else if (ret) {
+ /* function will have marked an error */
+ return;
+ }
+
+ kvm_arm_set_cpu_features_from_host(cpu, expose_id_regs);
if (arm_feature(&cpu->env, ARM_FEATURE_AARCH64)) {
aarch64_add_sve_properties(obj);
aarch64_add_pauth_properties(obj);
}
+ if (expose_id_regs) {
+ /* generate SYSREG properties according to writable masks */
+ kvm_arm_expose_idreg_properties(cpu, arm64_id_regs);
+ }
+
#elif defined(CONFIG_HVF)
ARMCPU *cpu = ARM_CPU(obj);
hvf_arm_set_cpu_features_from_host(cpu);
diff --git a/target/arm/kvm.c b/target/arm/kvm.c
index 9e4cca1705c8..63e27906cc42 100644
--- a/target/arm/kvm.c
+++ b/target/arm/kvm.c
@@ -335,6 +335,141 @@ static int get_host_cpu_idregs(ARMCPU *cpu, int fd,
ARMHostCPUFeatures *ahcf)
return err;
}
+static ARM64SysRegField *get_field(int i, ARM64SysReg *reg)
+{
+ GList *l;
+
+ for (l = reg->fields; l; l = l->next) {
+ ARM64SysRegField *field = (ARM64SysRegField *)l->data;
+
+ if (i >= field->lower && i <= field->upper) {
+ return field;
+ }
+ }
+ return NULL;
+}
+
+static void set_sysreg_prop(Object *obj, Visitor *v,
+ const char *name, void *opaque,
+ Error **errp)
+{
+ ARM64SysRegField *field = (ARM64SysRegField *)opaque;
+ ARMCPU *cpu = ARM_CPU(obj);
+ uint64_t *idregs = cpu->isar.idregs;
+ uint64_t old, value, mask;
+ int lower = field->lower;
+ int upper = field->upper;
+ int length = upper - lower + 1;
+ int index = field->index;
+
+ if (!visit_type_uint64(v, name, &value, errp)) {
+ return;
+ }
+
+ if (length < 64 && value > ((1 << length) - 1)) {
+ error_setg(errp,
+ "idreg %s set value (0x%lx) exceeds length of field (%d)!",
+ name, value, length);
+ return;
+ }
+
+ mask = MAKE_64BIT_MASK(lower, length);
+ value = value << lower;
+ old = idregs[index];
+ idregs[index] = old & ~mask;
+ idregs[index] |= value;
+ trace_set_sysreg_prop(name, old, mask, value, idregs[index]);
+}
+
+static void get_sysreg_prop(Object *obj, Visitor *v,
+ const char *name, void *opaque,
+ Error **errp)
+{
+ ARM64SysRegField *field = (ARM64SysRegField *)opaque;
+ ARMCPU *cpu = ARM_CPU(obj);
+ uint64_t *idregs = cpu->isar.idregs;
+ uint64_t value, mask;
+ int lower = field->lower;
+ int upper = field->upper;
+ int length = upper - lower + 1;
+ int index = field->index;
+
+ mask = MAKE_64BIT_MASK(lower, length);
+ value = (idregs[index] & mask) >> lower;
+ visit_type_uint64(v, name, &value, errp);
+ trace_get_sysreg_prop(name, value);
+}
+
+/*
+ * decode_idreg_writemap: Generate props for writable fields
+ *
+ * @obj: CPU object
+ * @index: index of the sysreg
+ * @map: writable map for the sysreg
+ * @reg: description of the sysreg
+ */
+static int
+decode_idreg_writemap(Object *obj, int index, uint64_t map, ARM64SysReg *reg)
+{
+ int i = ctz64(map);
+ int nb_sysreg_props = 0;
+
+ while (map) {
+
+ ARM64SysRegField *field = get_field(i, reg);
+ int lower, upper;
+ uint64_t mask;
+ char *prop_name;
+
+ if (!field) {
+ /* the field cannot be matched to any know id named field */
+ warn_report("%s bit %d of %s is writable but cannot be matched",
+ __func__, i, reg->name);
+ warn_report("%s is cpu-sysreg-properties.c up to date?", __func__);
+ map = map & ~BIT_ULL(i);
+ i = ctz64(map);
+ continue;
+ }
+ lower = field->lower;
+ upper = field->upper;
+ prop_name = g_strdup_printf("SYSREG_%s_%s", reg->name, field->name);
+ trace_decode_idreg_writemap(field->name, lower, upper, prop_name);
+ object_property_add(obj, prop_name, "uint64",
+ get_sysreg_prop, set_sysreg_prop, NULL, field);
+ nb_sysreg_props++;
+
+ mask = MAKE_64BIT_MASK(lower, upper - lower + 1);
+ map = map & ~mask;
+ i = ctz64(map);
+ }
+ trace_nb_sysreg_props(reg->name, nb_sysreg_props);
+ return 0;
+}
+
+/* analyze the writable mask and generate properties for writable fields */
+void kvm_arm_expose_idreg_properties(ARMCPU *cpu, ARM64SysReg *regs)
+{
+ int i, idx;
+ IdRegMap *map = cpu->writable_map;
+ Object *obj = OBJECT(cpu);
+
+ for (i = 0; i < NR_ID_REGS; i++) {
+ uint64_t mask = map->regs[i];
+
+ if (mask) {
+ /* reg @i has some writable fields, decode them */
+ idx = kvm_idx_to_idregs_idx(i);
+ if (idx < 0) {
+ /* no matching reg? */
+ warn_report("%s: reg %d writable, but not in list of idregs?",
+ __func__, i);
+ } else {
+ decode_idreg_writemap(obj, i, mask, ®s[idx]);
+ }
+ }
+ }
+}
+
static bool
kvm_arm_get_host_cpu_features(ARMCPU *cpu, ARMHostCPUFeatures *ahcf,
bool exhaustive)
diff --git a/target/arm/kvm_arm.h b/target/arm/kvm_arm.h
index 90ba4f7d8987..ba5de45f868c 100644
--- a/target/arm/kvm_arm.h
+++ b/target/arm/kvm_arm.h
@@ -157,6 +157,16 @@ void kvm_arm_set_cpu_features_from_host(ARMCPU *cpu, bool
exhaustive);
*/
void kvm_arm_add_vcpu_properties(ARMCPU *cpu);
+typedef struct ARM64SysReg ARM64SysReg;
+/**
+ * kvm_arm_expose_idreg_properties:
+ * @cpu: The CPU object to generate the properties for
+ * @reg: registers from the host
+ *
+ * analyze the writable mask and generate properties for writable fields
+ */
+void kvm_arm_expose_idreg_properties(ARMCPU *cpu, ARM64SysReg *regs);
+
/**
* kvm_arm_steal_time_finalize:
* @cpu: ARMCPU for which to finalize kvm-steal-time
diff --git a/target/arm/trace-events b/target/arm/trace-events
index 955149ee1ac4..8d2a234d5272 100644
--- a/target/arm/trace-events
+++ b/target/arm/trace-events
@@ -15,3 +15,7 @@ arm_gt_update_irq(int timer, int irqstate) "gt_update_irq:
timer %d irqstate %d"
kvm_arm_fixup_msi_route(uint64_t iova, uint64_t gpa) "MSI iova = 0x%"PRIx64"
is translated into 0x%"PRIx64
get_host_cpu_idregs(const char *name, uint64_t value) "scratch vcpu host value
for %s is 0x%"PRIx64
kvm_arm_writable_idregs_to_cpreg_list(const char *name, uint64_t previous,
uint64_t new) "%s overwrite default 0x%"PRIx64" with 0x%"PRIx64
+decode_idreg_writemap(const char* name, int lower, int upper, char *prop_name)
"%s [%d:%d] is writable (prop %s)"
+get_sysreg_prop(const char *name, uint64_t value) "%s 0x%"PRIx64
+set_sysreg_prop(const char *name, uint64_t old, uint64_t mask, uint64_t
field_value, uint64_t new) "%s old reg value=0x%"PRIx64" mask=0x%"PRIx64" new
field value=0x%"PRIx64" new reg value=0x%"PRIx64
+nb_sysreg_props(const char *name, int count) "%s: %d SYSREG properties"
--
2.49.0
