[libvirt] [PATCH] snapshot: ABI stability must include memory sizing
Michal Privoznik
mprivozn at redhat.com
Wed Sep 14 15:47:55 UTC 2011
On 13.09.2011 22:27, Eric Blake wrote:
> Commit 973fcd8f introduced the ability for qemu to reject snapshot
> reversion on an ABI incompatibility; but the very example that was
> first proposed on-list[1] as a demonstration of an ABI incompatibility,
> namely that of changing the max memory allocation, was not being
> checked for, resulting in a cryptic failure when running with larger
> max mem than what the snapshot was created with:
> error: operation failed: Error -22 while loading VM state
>
> This commit merely protects the three variables within mem that are
> referenced by qemu_command.c, rather than all 7 (the other 4 variables
> affect cgroup handling, but have no visible effect to the qemu guest).
>
> [1] https://www.redhat.com/archives/libvir-list/2010-December/msg00331.html
>
> * src/conf/domain_conf.c (virDomainDefCheckABIStability): Add
> memory sizing checks.
> ---
>
> See also https://bugzilla.redhat.com/show_bug.cgi?id=735553#c5
>
> src/conf/domain_conf.c | 20 ++++++++++++++++++++
> 1 files changed, 20 insertions(+), 0 deletions(-)
>
> diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c
> index 11755fe..996e0d5 100644
> --- a/src/conf/domain_conf.c
> +++ b/src/conf/domain_conf.c
> @@ -8229,6 +8229,26 @@ bool virDomainDefCheckABIStability(virDomainDefPtr src,
> goto cleanup;
> }
>
> + if (src->mem.max_balloon != dst->mem.max_balloon) {
> + virDomainReportError(VIR_ERR_CONFIG_UNSUPPORTED,
> + _("Target domain max memory %ld does not match source %ld"),
> + dst->mem.max_balloon, src->mem.max_balloon);
> + goto cleanup;
> + }
> + if (src->mem.cur_balloon != dst->mem.cur_balloon) {
> + virDomainReportError(VIR_ERR_CONFIG_UNSUPPORTED,
> + _("Target domain current memory %ld does not match source %ld"),
> + dst->mem.cur_balloon, src->mem.cur_balloon);
> + goto cleanup;
> + }
> + if (src->mem.hugepage_backed != dst->mem.hugepage_backed) {
> + virDomainReportError(VIR_ERR_CONFIG_UNSUPPORTED,
> + _("Target domain huge page backing %ld does not match source %ld"),
> + dst->mem.hugepage_backed,
> + src->mem.hugepage_backed);
> + goto cleanup;
> + }
> +
> if (src->vcpus != dst->vcpus) {
> virDomainReportError(VIR_ERR_CONFIG_UNSUPPORTED,
> _("Target domain vpu count %d does not match source %d"),
ACK
Michal
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