target-arm/kvm: make reg sync code common between kvm32/64

Before we launch a guest we query KVM for the list of "co-processor"
registers it knows about. This is used to synchronize system
register state for the bulk of coprocessor/system registers.
Move this code from the 32-bit specific vcpu init function into
a common routine and call it also from the 64-bit vcpu init.

This allows system registers to migrate correctly when using
KVM, and also permits QEMU code to see the current KVM register
state (which will be needed to support big-endian guests, since
the virtio endianness callback must check for some system register
settings).

Since vcpu reset also has to sync registers, we move the
32 bit kvm_arm_reset_vcpu() into common code as well and
share it with the 64 bit version.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
[PMM: just copy the 32-bit code rather than improving it along the way;
 don't share reg_syncs_via_tuple_list() between 32 and 64 bit;
 tweak function names; move reset]
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

1 files changed, 98 insertions, 0 deletions

diff --git a/target-arm/kvm.c b/target-arm/kvm.c
index 319784d689..191e759b3b 100644
--- a/target-arm/kvm.c
+++ b/target-arm/kvm.c
@@ -21,6 +21,7 @@
 #include "sysemu/kvm.h"
 #include "kvm_arm.h"
 #include "cpu.h"
+#include "internals.h"
 #include "hw/arm/arm.h"
 
 const KVMCapabilityInfo kvm_arch_required_capabilities[] = {
@@ -279,6 +280,94 @@ void kvm_arm_register_device(MemoryRegion *mr, uint64_t devid, uint64_t group,
     memory_region_ref(kd->mr);
 }
 
+static int compare_u64(const void *a, const void *b)
+{
+    if (*(uint64_t *)a > *(uint64_t *)b) {
+        return 1;
+    }
+    if (*(uint64_t *)a < *(uint64_t *)b) {
+        return -1;
+    }
+    return 0;
+}
+
+/* Initialize the CPUState's cpreg list according to the kernel's
+ * definition of what CPU registers it knows about (and throw away
+ * the previous TCG-created cpreg list).
+ */
+int kvm_arm_init_cpreg_list(ARMCPU *cpu)
+{
+    struct kvm_reg_list rl;
+    struct kvm_reg_list *rlp;
+    int i, ret, arraylen;
+    CPUState *cs = CPU(cpu);
+
+    rl.n = 0;
+    ret = kvm_vcpu_ioctl(cs, KVM_GET_REG_LIST, &rl);
+    if (ret != -E2BIG) {
+        return ret;
+    }
+    rlp = g_malloc(sizeof(struct kvm_reg_list) + rl.n * sizeof(uint64_t));
+    rlp->n = rl.n;
+    ret = kvm_vcpu_ioctl(cs, KVM_GET_REG_LIST, rlp);
+    if (ret) {
+        goto out;
+    }
+    /* Sort the list we get back from the kernel, since cpreg_tuples
+     * must be in strictly ascending order.
+     */
+    qsort(&rlp->reg, rlp->n, sizeof(rlp->reg[0]), compare_u64);
+
+    for (i = 0, arraylen = 0; i < rlp->n; i++) {
+        if (!kvm_arm_reg_syncs_via_cpreg_list(rlp->reg[i])) {
+            continue;
+        }
+        switch (rlp->reg[i] & KVM_REG_SIZE_MASK) {
+        case KVM_REG_SIZE_U32:
+        case KVM_REG_SIZE_U64:
+            break;
+        default:
+            fprintf(stderr, "Can't handle size of register in kernel list\n");
+            ret = -EINVAL;
+            goto out;
+        }
+
+        arraylen++;
+    }
+
+    cpu->cpreg_indexes = g_renew(uint64_t, cpu->cpreg_indexes, arraylen);
+    cpu->cpreg_values = g_renew(uint64_t, cpu->cpreg_values, arraylen);
+    cpu->cpreg_vmstate_indexes = g_renew(uint64_t, cpu->cpreg_vmstate_indexes,
+                                         arraylen);
+    cpu->cpreg_vmstate_values = g_renew(uint64_t, cpu->cpreg_vmstate_values,
+                                        arraylen);
+    cpu->cpreg_array_len = arraylen;
+    cpu->cpreg_vmstate_array_len = arraylen;
+
+    for (i = 0, arraylen = 0; i < rlp->n; i++) {
+        uint64_t regidx = rlp->reg[i];
+        if (!kvm_arm_reg_syncs_via_cpreg_list(regidx)) {
+            continue;
+        }
+        cpu->cpreg_indexes[arraylen] = regidx;
+        arraylen++;
+    }
+    assert(cpu->cpreg_array_len == arraylen);
+
+    if (!write_kvmstate_to_list(cpu)) {
+        /* Shouldn't happen unless kernel is inconsistent about
+         * what registers exist.
+         */
+        fprintf(stderr, "Initial read of kernel register state failed\n");
+        ret = -EINVAL;
+        goto out;
+    }
+
+out:
+    g_free(rlp);
+    return ret;
+}
+
 bool write_kvmstate_to_list(ARMCPU *cpu)
 {
     CPUState *cs = CPU(cpu);
@@ -351,6 +440,15 @@ bool write_list_to_kvmstate(ARMCPU *cpu)
     return ok;
 }
 
+void kvm_arm_reset_vcpu(ARMCPU *cpu)
+{
+    /* Re-init VCPU so that all registers are set to
+     * their respective reset values.
+     */
+    kvm_arm_vcpu_init(CPU(cpu));
+    write_kvmstate_to_list(cpu);
+}
+
 void kvm_arch_pre_run(CPUState *cs, struct kvm_run *run)
 {
 }