hmp: gpa2hva and gpa2hpa hostaddr command

These commands are useful when testing machine-check passthrough.
gpa2hva is useful to inject a MADV_HWPOISON madvise from gdb, while
gpa2hpa is useful to inject an error with the mce-inject kernel
module.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Message-Id: <1490021158-4469-1-git-send-email-pbonzini@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Message-Id: <20170420133058.12911-1-pbonzini@redhat.com>
Reviewed-by: NDr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: NDr. David Alan Gilbert <dgilbert@redhat.com>

hmp-commands.hx

@@ -523,6 +523,38 @@ Dump 80 16 bit values at the start of the video memory.
 0x000b8090: 0x0720 0x0720 0x0720 0x0720 0x0720 0x0720 0x0720 0x0720
 @end smallexample
 @end itemize
+ETEXI
+
+    {
+        .name       = "gpa2hva",
+        .args_type  = "addr:l",
+        .params     = "addr",
+        .help       = "print the host virtual address corresponding to a guest physical address",
+        .cmd        = hmp_gpa2hva,
+    },
+
+STEXI
+@item gpa2hva @var{addr}
+@findex gpa2hva
+Print the host virtual address at which the guest's physical address @var{addr}
+is mapped.
+ETEXI
+
+#ifdef CONFIG_LINUX
+    {
+        .name       = "gpa2hpa",
+        .args_type  = "addr:l",
+        .params     = "addr",
+        .help       = "print the host physical address corresponding to a guest physical address",
+        .cmd        = hmp_gpa2hpa,
+    },
+#endif
+
+STEXI
+@item gpa2hpa @var{addr}
+@findex gpa2hpa
+Print the host physical address at which the guest's physical address @var{addr}
+is mapped.
 ETEXI
 
     {

monitor.c

@@ -1421,6 +1421,107 @@ static void hmp_physical_memory_dump(Monitor *mon, const QDict *qdict)
     memory_dump(mon, count, format, size, addr, 1);
 }
 
+static void *gpa2hva(MemoryRegion **p_mr, hwaddr addr, Error **errp)
+{
+    MemoryRegionSection mrs = memory_region_find(get_system_memory(),
+                                                 addr, 1);
+
+    if (!mrs.mr) {
+        error_setg(errp, "No memory is mapped at address 0x%" HWADDR_PRIx, addr);
+        return NULL;
+    }
+
+    if (!memory_region_is_ram(mrs.mr) && !memory_region_is_romd(mrs.mr)) {
+        error_setg(errp, "Memory at address 0x%" HWADDR_PRIx "is not RAM", addr);
+        memory_region_unref(mrs.mr);
+        return NULL;
+    }
+
+    *p_mr = mrs.mr;
+    return qemu_map_ram_ptr(mrs.mr->ram_block, mrs.offset_within_region);
+}
+
+static void hmp_gpa2hva(Monitor *mon, const QDict *qdict)
+{
+    hwaddr addr = qdict_get_int(qdict, "addr");
+    Error *local_err = NULL;
+    MemoryRegion *mr = NULL;
+    void *ptr;
+
+    ptr = gpa2hva(&mr, addr, &local_err);
+    if (local_err) {
+        error_report_err(local_err);
+        return;
+    }
+
+    monitor_printf(mon, "Host virtual address for 0x%" HWADDR_PRIx
+                   " (%s) is %p\n",
+                   addr, mr->name, ptr);
+
+    memory_region_unref(mr);
+}
+
+#ifdef CONFIG_LINUX
+static uint64_t vtop(void *ptr, Error **errp)
+{
+    uint64_t pinfo;
+    uint64_t ret = -1;
+    uintptr_t addr = (uintptr_t) ptr;
+    uintptr_t pagesize = getpagesize();
+    off_t offset = addr / pagesize * sizeof(pinfo);
+    int fd;
+
+    fd = open("/proc/self/pagemap", O_RDONLY);
+    if (fd == -1) {
+        error_setg_errno(errp, errno, "Cannot open /proc/self/pagemap");
+        return -1;
+    }
+
+    /* Force copy-on-write if necessary.  */
+    atomic_add((uint8_t *)ptr, 0);
+
+    if (pread(fd, &pinfo, sizeof(pinfo), offset) != sizeof(pinfo)) {
+        error_setg_errno(errp, errno, "Cannot read pagemap");
+        goto out;
+    }
+    if ((pinfo & (1ull << 63)) == 0) {
+        error_setg(errp, "Page not present");
+        goto out;
+    }
+    ret = ((pinfo & 0x007fffffffffffffull) * pagesize) | (addr & (pagesize - 1));
+
+out:
+    close(fd);
+    return ret;
+}
+
+static void hmp_gpa2hpa(Monitor *mon, const QDict *qdict)
+{
+    hwaddr addr = qdict_get_int(qdict, "addr");
+    Error *local_err = NULL;
+    MemoryRegion *mr = NULL;
+    void *ptr;
+    uint64_t physaddr;
+
+    ptr = gpa2hva(&mr, addr, &local_err);
+    if (local_err) {
+        error_report_err(local_err);
+        return;
+    }
+
+    physaddr = vtop(ptr, &local_err);
+    if (local_err) {
+        error_report_err(local_err);
+    } else {
+        monitor_printf(mon, "Host physical address for 0x%" HWADDR_PRIx
+                       " (%s) is 0x%" PRIx64 "\n",
+                       addr, mr->name, (uint64_t) physaddr);
+    }
+
+    memory_region_unref(mr);
+}
+#endif
+
 static void do_print(Monitor *mon, const QDict *qdict)
 {
     int format = qdict_get_int(qdict, "format");