Re: [PATCH 1/1] xc_domain_restore: Allow QEMU to increase memory

[Hongyang Yang <yanghy@cn.fujitsu.com>]

This patch also fix a triple fault when guests running under COLO mode.
(XEN) d0v1 Over-allocation for domain 1: 524545 > 524544
(XEN) memory.c:155:d0v1 Could not allocate order=0 extent: id=1 memflags=0 (181 
of 235)
(XEN) d1v1 Triple fault - invoking HVM shutdown action 1

On 04/14/2015 12:09 AM, Don Slutz wrote:
> If QEMU has called on xc_domain_setmaxmem to add more memory for
> option ROMs, domain restore needs to also increase the memory.
>
> Signed-off-by: Don Slutz <dslutz@verizon.com>
> ---
> To see the hvmloader loader issue:
>
>    xl cre -p e1000x8.xfg
>    xl save e1000x8 e1000x8.save
>    xl restore e1000x8.save
>
> With e1000x8.xfg:
> -------------------------------------------------------------------------------
> builder = "hvm"
> device_model_args_hvm = [
>   "-monitor",
>   "pty",
>   "-boot",
>   "menu=on",
> ]
> device_model_version = "qemu-xen"
> disk = [
>   "/dev/etherd/e500.1,,xvda",
>   "/dev/etherd/e500.2,,xvdb",
>   "/dev/etherd/e500.3,,xvde",
>   "/local-isos/iso/centos/x86_64/CentOS-6.3-x86_64-bin-DVD1.iso,,hdc,cdrom",
>   "/local-isos/iso/centos/x86_64/CentOS-6.3-x86_64-bin-DVD2.iso,,hdd,cdrom",
> ]
> maxmem = "8192"
> memory = "8192"
> name = "e1000x8"
> serial = "pty"
> tsc_mode = "native_paravirt"
> uuid = "e5000105-3d83-c962-07ae-2bc46c3644a0"
> videoram = "16"
> vif = [
>   "model=e1000,bridge=xenbr0,mac=00:0c:29:86:44:a0",
>   "model=e1000,bridge=xenbr0,mac=00:0c:29:86:44:aa",
>   "model=e1000,bridge=xenbr0,mac=00:0c:29:86:44:b4",
>   "model=e1000,bridge=xenbr0,mac=00:0c:29:86:44:be",
>   "model=e1000,bridge=xenbr0,mac=00:0c:29:86:44:c8",
>   "model=e1000,bridge=xenbr0,mac=00:0c:29:86:44:d2",
>   "model=e1000,bridge=xenbr0,mac=00:0c:29:86:44:dc",
>   "model=e1000,bridge=xenbr0,mac=00:0c:29:86:44:e6",
>   "model=e1000,bridge=xenbr0,mac=00:0c:29:86:44:f0",
>   "model=e1000,bridge=xenbr0,mac=00:0c:29:86:44:fa",
> ]
> viridian = 0
> xen_platform_pci = 1
> mmio_hole = 2048
> vcpus = 1
> maxvcpus = 6
> on_poweroff = "preserve"
> on_reboot = "preserve"
> on_watchdog = "preserve"
> on_crash = "preserve"
> -------------------------------------------------------------------------------
>
>
>   tools/libxc/xc_domain_restore.c | 75 +++++++++++++++++++++++++++++++++++++++--
>   1 file changed, 73 insertions(+), 2 deletions(-)
>
> diff --git a/tools/libxc/xc_domain_restore.c b/tools/libxc/xc_domain_restore.c
> index 2ab9f46..28b4fa6 100644
> --- a/tools/libxc/xc_domain_restore.c
> +++ b/tools/libxc/xc_domain_restore.c
> @@ -47,6 +47,13 @@
>   #include <xen/hvm/ioreq.h>
>   #include <xen/hvm/params.h>
>
> +/* Leave some slack so that hvmloader does not complain about lack of
> + * memory at boot time ("Could not allocate order=0 extent").
> + * Once hvmloader is modified to cope with that situation without
> + * printing warning messages, QEMU_SPARE_PAGES can be removed.
> + */
> +#define QEMU_SPARE_PAGES 16
> +
>   struct restore_ctx {
>       unsigned long max_mfn; /* max mfn of the current host machine */
>       unsigned long hvirt_start; /* virtual starting address of the hypervisor */
> @@ -209,12 +216,44 @@ static int uncanonicalize_pagetable(
>           if (!ctx->hvm && ctx->superpages)
>               rc = alloc_superpage_mfns(xch, dom, ctx, nr_mfns);
>           else
> +        {
> +            xc_domaininfo_t info;
> +            unsigned long free_pages;
> +
> +            if ((xc_domain_getinfolist(xch, dom, 1, &info) != 1) ||
> +                (info.domain != dom)) {
> +                ERROR("Failed xc_domain_getinfolist for batch (uncanonicalize_pagetable)\n");
> +                errno = ENOMEM;
> +                return 0;
> +            }
> +            free_pages = info.max_pages - info.tot_pages;
> +            if (free_pages > QEMU_SPARE_PAGES) {
> +                free_pages -= QEMU_SPARE_PAGES;
> +            } else {
> +                free_pages = 0;
> +            }
> +            if (free_pages < nr_mfns)
> +            {
> +                DPRINTF("Adjust memory for batch (uncanonicalize_pagetable): free_pages=%lu nr_mfns=%d max_pages=%lu tot_pages=%lu max_mfn=%lu\n",
> +                        free_pages, nr_mfns, (unsigned long)info.max_pages,
> +                        (unsigned long)info.tot_pages, ctx->max_mfn);
> +                if (xc_domain_setmaxmem(xch, dom,
> +                                        ((info.max_pages + nr_mfns - free_pages)
> +                                         << (XC_PAGE_SHIFT - 10))) < 0)
> +                {
> +                    ERROR("Failed xc_domain_setmaxmem for batch (uncanonicalize_pagetable)\n");
> +                    errno = ENOMEM;
> +                    return 0;
> +                }
> +            }
>               rc = xc_domain_populate_physmap_exact(xch, dom, nr_mfns, 0, 0,
>                                                     ctx->p2m_batch);
> +        }
>
>           if (rc)
>           {
> -            ERROR("Failed to allocate memory for batch.!\n");
> +            ERROR("Failed to allocate memory for batch. rc=%d nr_mfns=%d!\n",
> +                  rc, nr_mfns);
>               errno = ENOMEM;
>               return 0;
>           }
> @@ -1241,12 +1280,44 @@ static int apply_batch(xc_interface *xch, uint32_t dom, struct restore_ctx *ctx,
>           if (!ctx->hvm && ctx->superpages)
>               rc = alloc_superpage_mfns(xch, dom, ctx, nr_mfns);
>           else
> +        {
> +            xc_domaininfo_t info;
> +            unsigned long free_pages;
> +
> +            if ((xc_domain_getinfolist(xch, dom, 1, &info) != 1) ||
> +                (info.domain != dom)) {
> +                ERROR("Failed xc_domain_getinfolist for apply_batch\n");
> +                errno = ENOMEM;
> +                return -1;
> +            }
> +            free_pages = info.max_pages - info.tot_pages;
> +            if (free_pages > QEMU_SPARE_PAGES) {
> +                free_pages -= QEMU_SPARE_PAGES;
> +            } else {
> +                free_pages = 0;
> +            }
> +            if (free_pages < nr_mfns)
> +            {
> +                DPRINTF("Adjust memory for apply_batch: free_pages=%lu nr_mfns=%d max_pages=%lu tot_pages=%lu max_mfn=%lu\n",
> +                        free_pages, nr_mfns, (unsigned long)info.max_pages,
> +                        (unsigned long)info.tot_pages, ctx->max_mfn);
> +                if (xc_domain_setmaxmem(xch, dom,
> +                                        ((info.max_pages + nr_mfns - free_pages)
> +                                         << (XC_PAGE_SHIFT - 10))) < 0)
> +                {
> +                    ERROR("Failed xc_domain_setmaxmem for apply_batch\n");
> +                    errno = ENOMEM;
> +                    return -1;
> +                }
> +            }
>               rc = xc_domain_populate_physmap_exact(xch, dom, nr_mfns, 0, 0,
>                                                     ctx->p2m_batch);
> +        }
>
>           if (rc)
>           {
> -            ERROR("Failed to allocate memory for batch.!\n");
> +            ERROR("Failed to allocate memory for apply_batch. rc=%d nr_mfns=%d max_mfn=%lu!\n",
> +                  rc, nr_mfns, ctx->max_mfn);
>               errno = ENOMEM;
>               return -1;
>           }
>

-- 
Thanks,
Yang.