@@ -23,6 +23,57 @@
#include "hw/s390x/pv.h"
#include "kvm_s390x.h"
+void handle_diag_260(CPUS390XState *env, uint64_t r1, uint64_t r3, uintptr_t ra)
+{
+ MachineState *ms = MACHINE(qdev_get_machine());
+ const ram_addr_t initial_ram_size = ms->ram_size;
+ const uint64_t subcode = env->regs[r3];
+
+ switch (subcode) {
+ case 0xc:
+ /* The first storage extent maps to our initial ram. */
+ env->regs[r1] = initial_ram_size - 1;
+ /* The highest addressable byte maps to the initial ram size for now. */
+ env->regs[r3] = initial_ram_size - 1;
+ break;
+ case 0x10: {
+ ram_addr_t addr, length;
+ uint64_t tmp;
+
+ if (r1 & 1) {
+ s390_program_interrupt(env, PGM_SPECIFICATION, ra);
+ return;
+ }
+
+ addr = env->regs[r1];
+ length = env->regs[r1 + 1];
+ if (!QEMU_IS_ALIGNED(addr, 16) || !QEMU_IS_ALIGNED(length, 16) ||
+ !length) {
+ s390_program_interrupt(env, PGM_SPECIFICATION, ra);
+ return;
+ }
+ if (!address_space_access_valid(&address_space_memory, addr, length,
+ true, MEMTXATTRS_UNSPECIFIED)) {
+ s390_program_interrupt(env, PGM_ADDRESSING, ra);
+ return;
+ }
+
+ /* Indicate our initial memory ([0 .. ram_size - 1]) */
+ tmp = cpu_to_be64(0);
+ cpu_physical_memory_write(addr, &tmp, sizeof(tmp));
+ tmp = cpu_to_be64(initial_ram_size - 1);
+ cpu_physical_memory_write(addr + sizeof(tmp), &tmp, sizeof(tmp));
+
+ /* Exactly one entry was stored, it always fits into the area. */
+ env->regs[r3] = 1;
+ setcc(env_archcpu(env), 0);
+ break;
+ }
+ default:
+ s390_program_interrupt(env, PGM_SPECIFICATION, ra);
+ }
+}
+
int handle_diag_288(CPUS390XState *env, uint64_t r1, uint64_t r3)
{
uint64_t func = env->regs[r1];
@@ -372,6 +372,8 @@ int mmu_translate_real(CPUS390XState *env, target_ulong raddr, int rw,
/* misc_helper.c */
+void handle_diag_260(CPUS390XState *env, uint64_t r1, uint64_t r3,
+ uintptr_t ra);
int handle_diag_288(CPUS390XState *env, uint64_t r1, uint64_t r3);
void handle_diag_308(CPUS390XState *env, uint64_t r1, uint64_t r3,
uintptr_t ra);
@@ -1565,6 +1565,14 @@ static int handle_hypercall(S390CPU *cpu, struct kvm_run *run)
return ret;
}
+static void kvm_handle_diag_260(S390CPU *cpu, struct kvm_run *run)
+{
+ const uint64_t r1 = (run->s390_sieic.ipa & 0x00f0) >> 4;
+ const uint64_t r3 = run->s390_sieic.ipa & 0x000f;
+
+ handle_diag_260(&cpu->env, r1, r3, 0);
+}
+
static void kvm_handle_diag_288(S390CPU *cpu, struct kvm_run *run)
{
uint64_t r1, r3;
@@ -1614,6 +1622,9 @@ static int handle_diag(S390CPU *cpu, struct kvm_run *run, uint32_t ipb)
*/
func_code = decode_basedisp_rs(&cpu->env, ipb, NULL) & DIAG_KVM_CODE_MASK;
switch (func_code) {
+ case 0x260:
+ kvm_handle_diag_260(cpu, run);
+ break;
case DIAG_TIMEREVENT:
kvm_handle_diag_288(cpu, run);
break;
@@ -116,6 +116,12 @@ void HELPER(diag)(CPUS390XState *env, uint32_t r1, uint32_t r3, uint32_t num)
uint64_t r;
switch (num) {
+ case 0x260:
+ qemu_mutex_lock_iothread();
+ handle_diag_260(env, r1, r3, GETPC());
+ qemu_mutex_unlock_iothread();
+ r = 0;
+ break;
case 0x500:
/* KVM hypercall */
qemu_mutex_lock_iothread();
@@ -2397,6 +2397,13 @@ static DisasJumpType op_diag(DisasContext *s, DisasOps *o)
TCGv_i32 r3 = tcg_const_i32(get_field(s, r3));
TCGv_i32 func_code = tcg_const_i32(get_field(s, i2));
+ /*
+ * Diag 0x260 updates the CC - only for some subcodes. Calculate the
+ * current cc, such that the helper can simply overwrite it conditionally.
+ */
+ if (get_field(s, i2) == 0x260) {
+ gen_op_calc_cc(s);
+ }
gen_helper_diag(cpu_env, r1, r3, func_code);
tcg_temp_free_i32(func_code);
Let's implement diag260 - "Access Certain Virtual Machine Information", used under z/VM to expose the storage configuration (especially, layout of storage extends and thereby holes). For now, the returned information is completely redundant to the information exposed via SCLP. We want to reuse diag260 in QEMU to implement memory devices - to have a mechanism to indicate to the guest OS that the initial ram size and the maximum possible physical address differ. The Linux kernel supports diag260 (0x10) to query the available memory since v4.20. Ancient Linux versions used diag 260 (0xc), but stopped doing so a while ago. Let's unconditionally implement the new diag, without any migration checks (e.g., compatibility machine, CPU model). Although a guest OS could observe this when migrating between QEMU evrsions, it's somewhat unlikely to ever trigger due to the way diag260 is used within a guest OS - called only once or twice during boot. Signed-off-by: David Hildenbrand <david@redhat.com> --- target/s390x/diag.c | 51 ++++++++++++++++++++++++++++++++++++++ target/s390x/internal.h | 2 ++ target/s390x/kvm.c | 11 ++++++++ target/s390x/misc_helper.c | 6 +++++ target/s390x/translate.c | 7 ++++++ 5 files changed, 77 insertions(+)