On 14/03/2017 18:57, Dr. David Alan Gilbert wrote:
> * Paolo Bonzini (pbonz...@redhat.com) wrote:
>> 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: Paolo Bonzini <pbonz...@redhat.com>
>> ---
>> Technically a feature, but on the other hand it is pretty
>> much impossible to test without it, and the people testing
>> the feature are using it as an out-of-tree patch. Opinions?
>
> I've no real objection except for the freeze; they're reasonable
> debug commands.
>
>> hmp-commands.hx | 32 ++++++++++++++++++
>> monitor.c | 103
>> ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
>> 2 files changed, 135 insertions(+)
>>
>> diff --git a/hmp-commands.hx b/hmp-commands.hx
>> index 8819281..0aca984 100644
>> --- a/hmp-commands.hx
>> +++ b/hmp-commands.hx
>> @@ -526,6 +526,38 @@ Dump 80 16 bit values at the start of the video memory.
>> 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
>> +
>> + {
>> .name = "p|print",
>> .args_type = "fmt:/,val:l",
>> .params = "/fmt expr",
>> diff --git a/monitor.c b/monitor.c
>> index be282ec..1ac8c5f 100644
>> --- a/monitor.c
>> +++ b/monitor.c
>> @@ -1421,6 +1421,109 @@ 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;
>> + 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;
>
> An odd value for a uint.
Call it an invalid physical address. :)
>> + uintptr_t addr = (uintptr_t) ptr;
>> + uintptr_t pagesize = getpagesize();
>> + off_t offset = addr / pagesize * sizeof (pinfo);
>> + char pagemapname[64];
>> + int fd;
>> +
>> + sprintf(pagemapname, "/proc/%d/pagemap", getpid());
>> + fd = open(pagemapname, O_RDONLY);
>
> /proc/self/pagemap would seem easier.
Ok.
>> + if (fd == -1) {
>> + error_setg_errno(errp, errno, "Cannot open %s", pagemapname);
>> + 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 from %s", pagemapname);
>> + goto out;
>> + }
>> + if ((pinfo & (1ull << 63)) == 0) {
>> + error_setg(errp, "Page not present");
>> + goto out;
>> + }
>> + ret = ((pinfo & 0x007fffffffffffffull) << 12) | (addr & (pagesize - 1));
>
> Is that an x86 magic 12 ?
> (life would seem to get messy if pagesize != 1<<12 for that line)
Yes, it is.
Paolo
