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Re: [Qemu-devel] [PATCH v6 6/7] exec: report error when memory < hpagesi
From: |
Peter Crosthwaite |
Subject: |
Re: [Qemu-devel] [PATCH v6 6/7] exec: report error when memory < hpagesize |
Date: |
Thu, 7 Aug 2014 21:45:04 +1000 |
On Thu, Aug 7, 2014 at 7:10 PM, Hu Tao <address@hidden> wrote:
> Report error when memory < hpagesize in file_ram_alloc() so callers can
"an error"
> handle the error.
>
> This patch fix a problem that if user adds a memory-backend-file object
Long sentence. I would drop the "This patch fixes a problem that"
> using object_add command, specifying a size that is less than huge page
> size, qemu will core dump with message:
>
> Bad ram offset fffffffffffff000
> Aborted (core dumped)
>
Then say here "This patch fixes the problem."
> with this patch, qemu reports error message like:
>
> qemu-system-x86_64: -object
> memory-backend-file,mem-path=/hugepages,id=mem-file0,size=1M: memory
> size 0x100000 must be equal to or larger than huge page size 0x200000
>
> Signed-off-by: Hu Tao <address@hidden>
> ---
> exec.c | 13 ++++++++-----
> 1 file changed, 8 insertions(+), 5 deletions(-)
>
> diff --git a/exec.c b/exec.c
> index accba00..50cd510 100644
> --- a/exec.c
> +++ b/exec.c
> @@ -1024,9 +1024,9 @@ static void *file_ram_alloc(RAMBlock *block,
> char *filename;
> char *sanitized_name;
> char *c;
> - void *area;
> + void *area = NULL;
> int fd;
> - unsigned long hpagesize;
> + uint64_t hpagesize;
>
> hpagesize = gethugepagesize(path);
> if (!hpagesize) {
> @@ -1034,7 +1034,10 @@ static void *file_ram_alloc(RAMBlock *block,
> }
>
> if (memory < hpagesize) {
> - return NULL;
> + error_setg(errp, "memory size 0x" RAM_ADDR_FMT " must be equal to "
> + "or larger than huge page size 0x%" PRIx64,
> + memory, hpagesize);
> + goto error;
> }
>
> if (kvm_enabled() && !kvm_has_sync_mmu()) {
> @@ -1094,8 +1097,8 @@ static void *file_ram_alloc(RAMBlock *block,
> return area;
>
> error:
> - if (mem_prealloc) {
> - exit(1);
So I get the movitation behind getting rid of the core dump and
abort(). But this seems like a different change. You are demoting an
explicit fatal error (which looks to me to be unhelpfully silent) to a
propagating error. What's the reasoning? Is there any awareness of the
must-exit on the mem_prealloc failure case in the higher levels?
Regards,
Peter
> + if (area && area != MAP_FAILED) {
> + munmap(area, memory);
> }
> return NULL;
> }
> --
> 1.9.3
>
>
- [Qemu-devel] [PATCH v6 0/7] memory API improvements and bug fixes for memory backends, Hu Tao, 2014/08/07
- [Qemu-devel] [PATCH v6 2/7] memory: add parameter errp to memory_region_init_ram, Hu Tao, 2014/08/07
- [Qemu-devel] [PATCH v6 3/7] memory: add parameter errp to memory_region_init_ram_ptr, Hu Tao, 2014/08/07
- [Qemu-devel] [PATCH v6 4/7] memory: add parameter errp to memory_region_init_rom_device, Hu Tao, 2014/08/07
- [Qemu-devel] [PATCH v6 5/7] hostmem-ram: don't exit qemu if size of memory-backend-ram is way too big, Hu Tao, 2014/08/07
- [Qemu-devel] [PATCH v6 6/7] exec: report error when memory < hpagesize, Hu Tao, 2014/08/07
- Re: [Qemu-devel] [PATCH v6 6/7] exec: report error when memory < hpagesize,
Peter Crosthwaite <=
- [Qemu-devel] [PATCH v6 7/7] exec: add parameter errp to gethugepagesize, Hu Tao, 2014/08/07
Re: [Qemu-devel] [PATCH v6 0/7] memory API improvements and bug fixes for memory backends, Peter Crosthwaite, 2014/08/07