[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-changelog] [xen stable-4.6] memory: fix return value handing of guest_remove_page()
commit d23eb82c8aeb992e406c721c35799cf2790fd2a2 Author: Andrew Cooper <andrew.cooper3@xxxxxxxxxx> AuthorDate: Tue Jun 20 16:40:48 2017 +0200 Commit: Jan Beulich <jbeulich@xxxxxxxx> CommitDate: Tue Jun 20 16:40:48 2017 +0200 memory: fix return value handing of guest_remove_page() Despite the description in mm.h, guest_remove_page() previously returned 0 for paging errors. Switch guest_remove_page() to having regular 0/-error semantics, and propagate the return values from clear_mmio_p2m_entry() and mem_sharing_unshare_page() to the callers (although decrease_reservation() is the only caller which currently cares). This is part of XSA-222. Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx> Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx> master commit: b614f642c35da5184416787352f51a6379a92628 master date: 2017-06-20 14:39:56 +0200 --- xen/common/memory.c | 34 +++++++++++++++++++++------------- xen/include/xen/mm.h | 3 +-- 2 files changed, 22 insertions(+), 15 deletions(-) diff --git a/xen/common/memory.c b/xen/common/memory.c index c2f0a77..c3d5ed6 100644 --- a/xen/common/memory.c +++ b/xen/common/memory.c @@ -240,6 +240,7 @@ int guest_remove_page(struct domain *d, unsigned long gmfn) p2m_type_t p2mt; #endif unsigned long mfn; + int rc; #ifdef CONFIG_X86 mfn = mfn_x(get_gfn_query(d, gmfn, &p2mt)); @@ -257,13 +258,15 @@ int guest_remove_page(struct domain *d, unsigned long gmfn) put_page(page); } p2m_mem_paging_drop_page(d, gmfn, p2mt); - return 1; + + return 0; } if ( p2mt == p2m_mmio_direct ) { - clear_mmio_p2m_entry(d, gmfn, _mfn(mfn)); + rc = clear_mmio_p2m_entry(d, gmfn, _mfn(mfn)); put_gfn(d, gmfn); - return 1; + + return rc; } #else mfn = gmfn_to_mfn(d, gmfn); @@ -273,21 +276,25 @@ int guest_remove_page(struct domain *d, unsigned long gmfn) put_gfn(d, gmfn); gdprintk(XENLOG_INFO, "Domain %u page number %lx invalid\n", d->domain_id, gmfn); - return 0; + + return -EINVAL; } #ifdef CONFIG_X86 if ( p2m_is_shared(p2mt) ) { - /* Unshare the page, bail out on error. We unshare because - * we might be the only one using this shared page, and we - * need to trigger proper cleanup. Once done, this is - * like any other page. */ - if ( mem_sharing_unshare_page(d, gmfn, 0) ) + /* + * Unshare the page, bail out on error. We unshare because we + * might be the only one using this shared page, and we need to + * trigger proper cleanup. Once done, this is like any other page. + */ + rc = mem_sharing_unshare_page(d, gmfn, 0); + if ( rc ) { put_gfn(d, gmfn); (void)mem_sharing_notify_enomem(d, gmfn, 0); - return 0; + + return rc; } /* Maybe the mfn changed */ mfn = mfn_x(get_gfn_query_unlocked(d, gmfn, &p2mt)); @@ -300,7 +307,8 @@ int guest_remove_page(struct domain *d, unsigned long gmfn) { put_gfn(d, gmfn); gdprintk(XENLOG_INFO, "Bad page free for domain %u\n", d->domain_id); - return 0; + + return -ENXIO; } if ( test_and_clear_bit(_PGT_pinned, &page->u.inuse.type_info) ) @@ -314,7 +322,7 @@ int guest_remove_page(struct domain *d, unsigned long gmfn) put_page(page); put_gfn(d, gmfn); - return 1; + return 0; } static void decrease_reservation(struct memop_args *a) @@ -365,7 +373,7 @@ static void decrease_reservation(struct memop_args *a) continue; for ( j = 0; j < (1 << a->extent_order); j++ ) - if ( !guest_remove_page(a->domain, gmfn + j) ) + if ( guest_remove_page(a->domain, gmfn + j) ) goto out; } diff --git a/xen/include/xen/mm.h b/xen/include/xen/mm.h index a795dd6..ea9052c 100644 --- a/xen/include/xen/mm.h +++ b/xen/include/xen/mm.h @@ -447,8 +447,7 @@ int xenmem_add_to_physmap_one(struct domain *d, unsigned int space, domid_t foreign_domid, unsigned long idx, xen_pfn_t gpfn); -/* Returns 1 on success, 0 on error, negative if the ring - * for event propagation is full in the presence of paging */ +/* Returns 0 on success, or negative on error. */ int guest_remove_page(struct domain *d, unsigned long gmfn); #define RAM_TYPE_CONVENTIONAL 0x00000001 -- generated by git-patchbot for /home/xen/git/xen.git#stable-4.6 _______________________________________________ Xen-changelog mailing list Xen-changelog@xxxxxxxxxxxxx https://lists.xenproject.org/xen-changelog
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