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No build reason found for SLE-Module-Development-Tools-OBS:aarch64
SUSE:SLE-12:Update
xen.8005
5949153f-x86-mm-disallow-page-stealing-from-HVM...
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File 5949153f-x86-mm-disallow-page-stealing-from-HVM-domains.patch of Package xen.8005
# Commit fae7d5be8bb8b7a5b7005c4f3b812a47661a721e # Date 2017-06-20 14:29:51 +0200 # Author Jan Beulich <jbeulich@suse.com> # Committer Jan Beulich <jbeulich@suse.com> x86/mm: disallow page stealing from HVM domains The operation's success can't be controlled by the guest, as the device model may have an active mapping of the page. If we nevertheless permitted this operation, we'd have to add further TLB flushing to prevent scenarios like "Domains A (HVM), B (PV), C (PV); B->target==A Steps: 1. B maps page X from A as writable 2. B unmaps page X without a TLB flush 3. A sends page X to C via GNTTABOP_transfer 4. C maps page X as pagetable (potentially causing a TLB flush in C, but not in B) At this point, X would be mapped as a pagetable in C while being writable through a stale TLB entry in B." A similar scenario could be constructed for A using XENMEM_exchange and some arbitrary PV domain C then having this page allocated. This is XSA-217. Reported-by: Jann Horn <jannh@google.com> Signed-off-by: Jan Beulich <jbeulich@suse.com> Acked-by: George Dunlap <george.dunlap@citrix.com> Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> --- a/xen/arch/x86/mm.c +++ b/xen/arch/x86/mm.c @@ -4219,6 +4219,9 @@ int steal_page( unsigned long x, y; bool_t drop_dom_ref = 0; + if ( paging_mode_external(d) ) + return -1; + spin_lock(&d->page_alloc_lock); if ( is_xen_heap_page(page) || (page_get_owner(page) != d) )
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