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Re: [Qemu-devel] [PULL] Urgent memory fix for kvm with unaligned memory
From: |
Bobby Powers |
Subject: |
Re: [Qemu-devel] [PULL] Urgent memory fix for kvm with unaligned memory slots |
Date: |
Thu, 1 Mar 2012 11:51:21 -0500 |
On Thu, Mar 1, 2012 at 8:40 AM, Avi Kivity <address@hidden> wrote:
> The memory core may generate RAM memory regions that are not page
> aligned, but the kvm code is not prepared to handle them well and will
> abort under certain conditions. This patch fixes the problem.
>
> Please pull from:
>
> git://git.kernel.org/pub/scm/virt/kvm/qemu-kvm.git memory/urgent
>
> ----------------------------------------------------------------
> Avi Kivity (1):
> kvm: fix unaligned slots
>
> kvm-all.c | 15 ++++++++++++---
> 1 files changed, 12 insertions(+), 3 deletions(-)
>
> diff --git a/kvm-all.c b/kvm-all.c
> index c4babda..4b7a4ae 100644
> --- a/kvm-all.c
> +++ b/kvm-all.c
> @@ -541,17 +541,26 @@ static void kvm_set_phys_mem(MemoryRegionSection
> *section, bool add)
> target_phys_addr_t start_addr = section->offset_within_address_space;
> ram_addr_t size = section->size;
> void *ram = NULL;
> + unsigned delta;
>
> /* kvm works in page size chunks, but the function may be called
> with sub-page size and unaligned start address. */
> - size = TARGET_PAGE_ALIGN(size);
> - start_addr = TARGET_PAGE_ALIGN(start_addr);
> + delta = TARGET_PAGE_ALIGN(size) - size;
> + if (delta > size) {
> + return;
> + }
> + start_addr += delta;
> + size -= delta;
> + size &= TARGET_PAGE_MASK;
> + if (!size || (start_addr & ~TARGET_PAGE_MASK)) {
> + return;
> + }
>
> if (!memory_region_is_ram(mr)) {
> return;
> }
>
> - ram = memory_region_get_ram_ptr(mr) + section->offset_within_region;
> + ram = memory_region_get_ram_ptr(mr) + section->offset_within_region
> + delta;
Am I crazy, or does this look wrong?
>
> while (1) {
> mem = kvm_lookup_overlapping_slot(s, start_addr, start_addr +
> size);
>
> --
> error compiling committee.c: too many arguments to function
>
> --
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