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Re: [Qemu-devel] [PATCH for 2.9?] hmp: gpa2hva and gpa2hpa hostaddr comm
From: |
Dr. David Alan Gilbert |
Subject: |
Re: [Qemu-devel] [PATCH for 2.9?] hmp: gpa2hva and gpa2hpa hostaddr command |
Date: |
Tue, 14 Mar 2017 17:57:05 +0000 |
User-agent: |
Mutt/1.7.1 (2016-10-04) |
* Paolo Bonzini (address@hidden) 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 <address@hidden>
> ---
> 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
> address@hidden gpa2hva @var{addr}
> address@hidden 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
> address@hidden gpa2hpa @var{addr}
> address@hidden 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.
> + 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.
> + 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)
> +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;
> + 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");
Dave
> --
> 1.8.3.1
>
--
Dr. David Alan Gilbert / address@hidden / Manchester, UK