s390x/kvm: rework KVM synchronize to tracing for some ONEREGS

Some ONE_REGS on s390 are not protected by a capability. Older kernels
might not provide those and return an error. Fortunately these registers
are only critical for the migration path. There is no need to error out
on reset and normal runtime. Furthermore, these kernels don't provide
a proper dirty bitmap anyway, so let's use tracing for those errors.

Also provide generic one reg helper to simplify the code.

Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
(cherry picked from commit 860643bc5aa902f9b736c57b66e301ef08a2b68e)
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>

diff --git a/target-s390x/kvm.c b/target-s390x/kvm.c
index 2b2dcdc4854cb3f14046f1ff1cf51c054d40fb2b..daaabbd6741a497a620c556d3d838484ab97eb8a 100644 (file)
--- a/target-s390x/kvm.c
+++ b/target-s390x/kvm.c
@@ -36,6 +36,7 @@
 #include "sysemu/device_tree.h"
 #include "qapi/qmp/qjson.h"
 #include "monitor/monitor.h"
+#include "trace.h"
 
 /* #define DEBUG_KVM */
 
@@ -128,14 +129,42 @@ void kvm_arch_reset_vcpu(CPUState *cpu)
     }
 }
 
+static int kvm_set_one_reg(CPUState *cs, uint64_t id, void *source)
+{
+    struct kvm_one_reg reg;
+    int r;
+
+    reg.id = id;
+    reg.addr = (uint64_t) source;
+    r = kvm_vcpu_ioctl(cs, KVM_SET_ONE_REG, &reg);
+    if (r) {
+        trace_kvm_failed_reg_set(id, strerror(errno));
+    }
+    return r;
+}
+
+static int kvm_get_one_reg(CPUState *cs, uint64_t id, void *target)
+{
+    struct kvm_one_reg reg;
+    int r;
+
+    reg.id = id;
+    reg.addr = (uint64_t) target;
+    r = kvm_vcpu_ioctl(cs, KVM_GET_ONE_REG, &reg);
+    if (r) {
+        trace_kvm_failed_reg_get(id, strerror(errno));
+    }
+    return r;
+}
+
+
 int kvm_arch_put_registers(CPUState *cs, int level)
 {
     S390CPU *cpu = S390_CPU(cs);
     CPUS390XState *env = &cpu->env;
-    struct kvm_one_reg reg;
     struct kvm_sregs sregs;
     struct kvm_regs regs;
-    int ret;
+    int r;
     int i;
 
     /* always save the PSW  and the GPRS*/
@@ -151,9 +180,9 @@ int kvm_arch_put_registers(CPUState *cs, int level)
         for (i = 0; i < 16; i++) {
             regs.gprs[i] = env->regs[i];
         }
-        ret = kvm_vcpu_ioctl(cs, KVM_SET_REGS, &regs);
-        if (ret < 0) {
-            return ret;
+        r = kvm_vcpu_ioctl(cs, KVM_SET_REGS, &regs);
+        if (r < 0) {
+            return r;
         }
     }
 
@@ -162,47 +191,27 @@ int kvm_arch_put_registers(CPUState *cs, int level)
         return 0;
     }
 
-    reg.id = KVM_REG_S390_CPU_TIMER;
-    reg.addr = (__u64)&(env->cputm);
-    ret = kvm_vcpu_ioctl(cs, KVM_SET_ONE_REG, &reg);
-    if (ret < 0) {
-        return ret;
-    }
-
-    reg.id = KVM_REG_S390_CLOCK_COMP;
-    reg.addr = (__u64)&(env->ckc);
-    ret = kvm_vcpu_ioctl(cs, KVM_SET_ONE_REG, &reg);
-    if (ret < 0) {
-        return ret;
-    }
-
-    reg.id = KVM_REG_S390_TODPR;
-    reg.addr = (__u64)&(env->todpr);
-    ret = kvm_vcpu_ioctl(cs, KVM_SET_ONE_REG, &reg);
-    if (ret < 0) {
-        return ret;
-    }
+    /*
+     * These ONE_REGS are not protected by a capability. As they are only
+     * necessary for migration we just trace a possible error, but don't
+     * return with an error return code.
+     */
+    kvm_set_one_reg(cs, KVM_REG_S390_CPU_TIMER, &env->cputm);
+    kvm_set_one_reg(cs, KVM_REG_S390_CLOCK_COMP, &env->ckc);
+    kvm_set_one_reg(cs, KVM_REG_S390_TODPR, &env->todpr);
 
     if (cap_async_pf) {
-        reg.id = KVM_REG_S390_PFTOKEN;
-        reg.addr = (__u64)&(env->pfault_token);
-        ret = kvm_vcpu_ioctl(cs, KVM_SET_ONE_REG, &reg);
-        if (ret < 0) {
-            return ret;
+        r = kvm_set_one_reg(cs, KVM_REG_S390_PFTOKEN, &env->pfault_token);
+        if (r < 0) {
+            return r;
         }
-
-        reg.id = KVM_REG_S390_PFCOMPARE;
-        reg.addr = (__u64)&(env->pfault_compare);
-        ret = kvm_vcpu_ioctl(cs, KVM_SET_ONE_REG, &reg);
-        if (ret < 0) {
-            return ret;
+        r = kvm_set_one_reg(cs, KVM_REG_S390_PFCOMPARE, &env->pfault_compare);
+        if (r < 0) {
+            return r;
         }
-
-        reg.id = KVM_REG_S390_PFSELECT;
-        reg.addr = (__u64)&(env->pfault_select);
-        ret = kvm_vcpu_ioctl(cs, KVM_SET_ONE_REG, &reg);
-        if (ret < 0) {
-            return ret;
+        r = kvm_set_one_reg(cs, KVM_REG_S390_PFSELECT, &env->pfault_select);
+        if (r < 0) {
+            return r;
         }
     }
 
@@ -220,9 +229,9 @@ int kvm_arch_put_registers(CPUState *cs, int level)
             sregs.acrs[i] = env->aregs[i];
             sregs.crs[i] = env->cregs[i];
         }
-        ret = kvm_vcpu_ioctl(cs, KVM_SET_SREGS, &sregs);
-        if (ret < 0) {
-            return ret;
+        r = kvm_vcpu_ioctl(cs, KVM_SET_SREGS, &sregs);
+        if (r < 0) {
+            return r;
         }
     }
 
@@ -240,7 +249,6 @@ int kvm_arch_get_registers(CPUState *cs)
 {
     S390CPU *cpu = S390_CPU(cs);
     CPUS390XState *env = &cpu->env;
-    struct kvm_one_reg reg;
     struct kvm_sregs sregs;
     struct kvm_regs regs;
     int i, r;
@@ -288,46 +296,25 @@ int kvm_arch_get_registers(CPUState *cs)
         env->psa = cs->kvm_run->s.regs.prefix;
     }
 
-    /* One Regs */
-    reg.id = KVM_REG_S390_CPU_TIMER;
-    reg.addr = (__u64)&(env->cputm);
-    r = kvm_vcpu_ioctl(cs, KVM_GET_ONE_REG, &reg);
-    if (r < 0) {
-        return r;
-    }
-
-    reg.id = KVM_REG_S390_CLOCK_COMP;
-    reg.addr = (__u64)&(env->ckc);
-    r = kvm_vcpu_ioctl(cs, KVM_GET_ONE_REG, &reg);
-    if (r < 0) {
-        return r;
-    }
-
-    reg.id = KVM_REG_S390_TODPR;
-    reg.addr = (__u64)&(env->todpr);
-    r = kvm_vcpu_ioctl(cs, KVM_GET_ONE_REG, &reg);
-    if (r < 0) {
-        return r;
-    }
+    /*
+     * These ONE_REGS are not protected by a capability. As they are only
+     * necessary for migration we just trace a possible error, but don't
+     * return with an error return code.
+     */
+    kvm_get_one_reg(cs, KVM_REG_S390_CPU_TIMER, &env->cputm);
+    kvm_get_one_reg(cs, KVM_REG_S390_CLOCK_COMP, &env->ckc);
+    kvm_get_one_reg(cs, KVM_REG_S390_TODPR, &env->todpr);
 
     if (cap_async_pf) {
-        reg.id = KVM_REG_S390_PFTOKEN;
-        reg.addr = (__u64)&(env->pfault_token);
-        r = kvm_vcpu_ioctl(cs, KVM_GET_ONE_REG, &reg);
+        r = kvm_get_one_reg(cs, KVM_REG_S390_PFTOKEN, &env->pfault_token);
         if (r < 0) {
             return r;
         }
-
-        reg.id = KVM_REG_S390_PFCOMPARE;
-        reg.addr = (__u64)&(env->pfault_compare);
-        r = kvm_vcpu_ioctl(cs, KVM_GET_ONE_REG, &reg);
+        r = kvm_get_one_reg(cs, KVM_REG_S390_PFCOMPARE, &env->pfault_compare);
         if (r < 0) {
             return r;
         }
-
-        reg.id = KVM_REG_S390_PFSELECT;
-        reg.addr = (__u64)&(env->pfault_select);
-        r = kvm_vcpu_ioctl(cs, KVM_GET_ONE_REG, &reg);
+        r = kvm_get_one_reg(cs, KVM_REG_S390_PFSELECT, &env->pfault_select);
         if (r < 0) {
             return r;
         }

diff --git a/trace-events b/trace-events
index d97a7cfc9b63d66c27deee5b2ff17733f4103ff6..37e52ff4d690d0b4f43b8b1a642fcc7c692ea584 100644 (file)
--- a/trace-events
+++ b/trace-events
@@ -1223,3 +1223,7 @@ xen_pv_mmio_write(uint64_t addr) "WARNING: write to Xen PV Device MMIO space (ad
 # hw/pci/pci_host.c
 pci_cfg_read(const char *dev, unsigned devid, unsigned fnid, unsigned offs, unsigned val) "%s %02u:%u @0x%x -> 0x%x"
 pci_cfg_write(const char *dev, unsigned devid, unsigned fnid, unsigned offs, unsigned val) "%s %02u:%u @0x%x <- 0x%x"
+
+# target-s390/kvm.c
+kvm_failed_reg_get(uint64_t id, const char *msg) "Warning: Unable to retrieve ONEREG %" PRIu64 " from KVM: %s"
+kvm_failed_reg_set(uint64_t id, const char *msg) "Warning: Unable to set ONEREG %" PRIu64 " to KVM: %s"