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| author | Boris Ostrovsky <boris.ostrovsky@oracle.com> | 2013-09-09 14:44:26 +0400 |
|---|---|---|
| committer | Stefano Stabellini <stefano.stabellini@eu.citrix.com> | 2013-09-09 14:50:52 +0400 |
| commit | d7f8f48d1eb3186b1b80b2ed9a7adab191f753e9 (patch) | |
| tree | 712a6bf69b28b03a0defce46f7289d4cfba94eb0 /arch/x86 | |
| parent | 9dd4b2944c46e1fdbd0a516c221c8a2670cbf005 (diff) | |
| download | linux-d7f8f48d1eb3186b1b80b2ed9a7adab191f753e9.tar.xz | |
xen/p2m: Don't call get_balloon_scratch_page() twice, keep interrupts disabled for multicalls
m2p_remove_override() calls get_balloon_scratch_page() in
MULTI_update_va_mapping() even though it already has pointer to this page from
the earlier call (in scratch_page). This second call doesn't have a matching
put_balloon_scratch_page() thus not restoring preempt count back. (Also, there
is no put_balloon_scratch_page() in the error path.)
In addition, the second multicall uses __xen_mc_entry() which does not disable
interrupts. Rearrange xen_mc_* calls to keep interrupts off while performing
multicalls.
This commit fixes a regression introduced by:
commit ee0726407feaf504dff304fb603652fb2d778b42
Author: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Date: Tue Jul 23 17:23:54 2013 +0000
xen/m2p: use GNTTABOP_unmap_and_replace to reinstate the original mapping
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Reviewed-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Diffstat (limited to 'arch/x86')
| -rw-r--r-- | arch/x86/xen/p2m.c | 10 |
1 files changed, 6 insertions, 4 deletions
diff --git a/arch/x86/xen/p2m.c b/arch/x86/xen/p2m.c index 0d4ec35895d4..8b901e8d782d 100644 --- a/arch/x86/xen/p2m.c +++ b/arch/x86/xen/p2m.c @@ -990,10 +990,13 @@ int m2p_remove_override(struct page *page, printk(KERN_WARNING "m2p_remove_override: " "pfn %lx mfn %lx, failed to modify kernel mappings", pfn, mfn); + put_balloon_scratch_page(); return -1; } - mcs = xen_mc_entry( + xen_mc_batch(); + + mcs = __xen_mc_entry( sizeof(struct gnttab_unmap_and_replace)); unmap_op = mcs.args; unmap_op->host_addr = kmap_op->host_addr; @@ -1003,12 +1006,11 @@ int m2p_remove_override(struct page *page, MULTI_grant_table_op(mcs.mc, GNTTABOP_unmap_and_replace, unmap_op, 1); - xen_mc_issue(PARAVIRT_LAZY_MMU); - mcs = __xen_mc_entry(0); MULTI_update_va_mapping(mcs.mc, scratch_page_address, - pfn_pte(page_to_pfn(get_balloon_scratch_page()), + pfn_pte(page_to_pfn(scratch_page), PAGE_KERNEL_RO), 0); + xen_mc_issue(PARAVIRT_LAZY_MMU); kmap_op->host_addr = 0; |