[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH] tools/migrate: Prevent PTE truncation from being fatal duing the live phase
It is possible, when normalising a PV pagetable that the table has been freed and reused for something else by the guest. In such a case, data read might no longer be a pagetable, and fail the truncation check. However, this should only be fatal if we encounter such a page in the paused phase. This check is now consistent with all other checks in the same area. Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx> --- CC: Ian Jackson <Ian.Jackson@xxxxxxxxxxxxx> CC: Wei Liu <wei.liu2@xxxxxxxxxx> This was hit by OSSTest: http://logs.test-lab.xenproject.org/osstest/logs/100684/test-amd64-i386-xl-raw/16.ts-guest-localmigrate.log The patch is untested, but the only plausible option given the circumstances. --- tools/libxc/xc_sr_save_x86_pv.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) diff --git a/tools/libxc/xc_sr_save_x86_pv.c b/tools/libxc/xc_sr_save_x86_pv.c index 7043409..f218d17 100644 --- a/tools/libxc/xc_sr_save_x86_pv.c +++ b/tools/libxc/xc_sr_save_x86_pv.c @@ -949,9 +949,14 @@ static int normalise_pagetable(struct xc_sr_context *ctx, const uint64_t *src, #ifdef __i386__ if ( mfn == INVALID_MFN ) { - ERROR("PTE truncation detected. L%lu[%u] = %016"PRIx64, - type >> XEN_DOMCTL_PFINFO_LTAB_SHIFT, i, pte); - errno = E2BIG; + if ( !ctx->dominfo.paused ) + errno = EAGAIN; + else + { + ERROR("PTE truncation detected. L%lu[%u] = %016"PRIx64, + type >> XEN_DOMCTL_PFINFO_LTAB_SHIFT, i, pte); + errno = E2BIG; + } return -1; } #endif -- 2.1.4 _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx https://lists.xen.org/xen-devel
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