From: William Roche <william.roche@oracle.com>

The SIGBUS signal siginfo reporting a HW memory error
provides a si_addr_lsb fields with an indication of the
impacted memory page size.
This information should be used to track the hwpoisoned
page sizes.

Signed-off-by: William Roche <william.roche@oracle.com>
---
 accel/kvm/kvm-all.c    | 6 ++++--
 accel/stubs/kvm-stub.c | 4 ++--
 include/qemu/osdep.h   | 5 +++--
 include/sysemu/kvm.h   | 4 ++--
 system/cpus.c          | 6 ++++--
 util/oslib-posix.c     | 3 +++
 6 files changed, 18 insertions(+), 10 deletions(-)

diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c
index 75d11a07b2..409c5d3ce6 100644
--- a/accel/kvm/kvm-all.c
+++ b/accel/kvm/kvm-all.c
@@ -2836,6 +2836,7 @@ void kvm_cpu_synchronize_pre_loadvm(CPUState *cpu)
 #ifdef KVM_HAVE_MCE_INJECTION
 static __thread void *pending_sigbus_addr;
 static __thread int pending_sigbus_code;
+static __thread short pending_sigbus_addr_lsb;
 static __thread bool have_sigbus_pending;
 #endif
 
@@ -3542,7 +3543,7 @@ void kvm_init_cpu_signals(CPUState *cpu)
 }
 
 /* Called asynchronously in VCPU thread.  */
-int kvm_on_sigbus_vcpu(CPUState *cpu, int code, void *addr)
+int kvm_on_sigbus_vcpu(CPUState *cpu, int code, void *addr, short addr_lsb)
 {
 #ifdef KVM_HAVE_MCE_INJECTION
     if (have_sigbus_pending) {
@@ -3551,6 +3552,7 @@ int kvm_on_sigbus_vcpu(CPUState *cpu, int code, void *addr)
     have_sigbus_pending = true;
     pending_sigbus_addr = addr;
     pending_sigbus_code = code;
+    pending_sigbus_addr_lsb = addr_lsb;
     qatomic_set(&cpu->exit_request, 1);
     return 0;
 #else
@@ -3559,7 +3561,7 @@ int kvm_on_sigbus_vcpu(CPUState *cpu, int code, void *addr)
 }
 
 /* Called synchronously (via signalfd) in main thread.  */
-int kvm_on_sigbus(int code, void *addr)
+int kvm_on_sigbus(int code, void *addr, short addr_lsb)
 {
 #ifdef KVM_HAVE_MCE_INJECTION
     /* Action required MCE kills the process if SIGBUS is blocked.  Because
diff --git a/accel/stubs/kvm-stub.c b/accel/stubs/kvm-stub.c
index 8e0eb22e61..80780433d8 100644
--- a/accel/stubs/kvm-stub.c
+++ b/accel/stubs/kvm-stub.c
@@ -38,12 +38,12 @@ bool kvm_has_sync_mmu(void)
     return false;
 }
 
-int kvm_on_sigbus_vcpu(CPUState *cpu, int code, void *addr)
+int kvm_on_sigbus_vcpu(CPUState *cpu, int code, void *addr, short addr_lsb)
 {
     return 1;
 }
 
-int kvm_on_sigbus(int code, void *addr)
+int kvm_on_sigbus(int code, void *addr, short addr_lsb)
 {
     return 1;
 }
diff --git a/include/qemu/osdep.h b/include/qemu/osdep.h
index fe7c3c5f67..838271c4b8 100644
--- a/include/qemu/osdep.h
+++ b/include/qemu/osdep.h
@@ -585,8 +585,9 @@ struct qemu_signalfd_siginfo {
     uint64_t ssi_stime;   /* System CPU time consumed (SIGCHLD) */
     uint64_t ssi_addr;    /* Address that generated signal
                              (for hardware-generated signals) */
-    uint8_t  pad[48];     /* Pad size to 128 bytes (allow for
-                             additional fields in the future) */
+    uint16_t ssi_addr_lsb;/* Least significant bit of address (SIGBUS) */
+    uint8_t  pad[46];     /* Pad size to 128 bytes (allow for */
+                          /* additional fields in the future) */
 };
 
 int qemu_signalfd(const sigset_t *mask);
diff --git a/include/sysemu/kvm.h b/include/sysemu/kvm.h
index 9cf14ca3d5..21262eb970 100644
--- a/include/sysemu/kvm.h
+++ b/include/sysemu/kvm.h
@@ -207,8 +207,8 @@ int kvm_has_gsi_routing(void);
 bool kvm_arm_supports_user_irq(void);
 
 
-int kvm_on_sigbus_vcpu(CPUState *cpu, int code, void *addr);
-int kvm_on_sigbus(int code, void *addr);
+int kvm_on_sigbus_vcpu(CPUState *cpu, int code, void *addr, short addr_lsb);
+int kvm_on_sigbus(int code, void *addr, short addr_lsb);
 
 #ifdef COMPILING_PER_TARGET
 #include "cpu.h"
diff --git a/system/cpus.c b/system/cpus.c
index 1c818ff682..12e630f760 100644
--- a/system/cpus.c
+++ b/system/cpus.c
@@ -376,12 +376,14 @@ static void sigbus_handler(int n, siginfo_t *siginfo, void *ctx)
 
     if (current_cpu) {
         /* Called asynchronously in VCPU thread.  */
-        if (kvm_on_sigbus_vcpu(current_cpu, siginfo->si_code, siginfo->si_addr)) {
+        if (kvm_on_sigbus_vcpu(current_cpu, siginfo->si_code,
+                               siginfo->si_addr, siginfo->si_addr_lsb)) {
             sigbus_reraise();
         }
     } else {
         /* Called synchronously (via signalfd) in main thread.  */
-        if (kvm_on_sigbus(siginfo->si_code, siginfo->si_addr)) {
+        if (kvm_on_sigbus(siginfo->si_code,
+                          siginfo->si_addr, siginfo->si_addr_lsb)) {
             sigbus_reraise();
         }
     }
diff --git a/util/oslib-posix.c b/util/oslib-posix.c
index 11b35e48fb..64517d1e40 100644
--- a/util/oslib-posix.c
+++ b/util/oslib-posix.c
@@ -767,6 +767,9 @@ void sigaction_invoke(struct sigaction *action,
     } else if (info->ssi_signo == SIGILL || info->ssi_signo == SIGFPE ||
                info->ssi_signo == SIGSEGV || info->ssi_signo == SIGBUS) {
         si.si_addr = (void *)(uintptr_t)info->ssi_addr;
+        if (info->ssi_signo == SIGBUS) {
+            si.si_addr_lsb = (short int)info->ssi_addr_lsb;
+        }
     } else if (info->ssi_signo == SIGCHLD) {
         si.si_pid = info->ssi_pid;
         si.si_status = info->ssi_status;
-- 
2.43.5