[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] patch x86-xen-disable-highmem-pte-allocation-even-when-config_highpte-y.patch added to 2.6.32-stable tree
This is a note to let you know that we have just queued up the patch titled Subject: x86, xen: Disable highmem PTE allocation even when CONFIG_HIGHPTE=y to the 2.6.32-stable tree. Its filename is x86-xen-disable-highmem-pte-allocation-even-when-config_highpte-y.patch A git repo of this tree can be found at http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary >From 817a824b75b1475f1b067c8cee318c7b4d66fcde Mon Sep 17 00:00:00 2001 From: Ian Campbell <ian.campbell@xxxxxxxxxx> Date: Fri, 26 Feb 2010 17:16:00 +0000 Subject: x86, xen: Disable highmem PTE allocation even when CONFIG_HIGHPTE=y MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Ian Campbell <ian.campbell@xxxxxxxxxx> commit 817a824b75b1475f1b067c8cee318c7b4d66fcde upstream. There's a path in the pagefault code where the kernel deliberately breaks its own locking rules by kmapping a high pte page without holding the pagetable lock (in at least page_check_address). This breaks Xen's ability to track the pinned/unpinned state of the page. There does not appear to be a viable workaround for this behaviour so simply disable HIGHPTE for all Xen guests. Signed-off-by: Ian Campbell <ian.campbell@xxxxxxxxxx> LKML-Reference: <1267204562-11844-1-git-send-email-ian.campbell@xxxxxxxxxx> Cc: Jeremy Fitzhardinge <jeremy@xxxxxxxx> Cc: Ingo Molnar <mingo@xxxxxxx> Cc: Pasi KÃrkkÃinen <pasik@xxxxxx> Cc: <xen-devel@xxxxxxxxxxxxxxxxxxx> Signed-off-by: H. Peter Anvin <hpa@xxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx> --- arch/x86/xen/enlighten.c | 7 +++++++ arch/x86/xen/mmu.c | 11 ++++++----- 2 files changed, 13 insertions(+), 5 deletions(-) --- a/arch/x86/xen/enlighten.c +++ b/arch/x86/xen/enlighten.c @@ -48,6 +48,7 @@ #include <asm/traps.h> #include <asm/setup.h> #include <asm/desc.h> +#include <asm/pgalloc.h> #include <asm/pgtable.h> #include <asm/tlbflush.h> #include <asm/reboot.h> @@ -1092,6 +1093,12 @@ asmlinkage void __init xen_start_kernel( __supported_pte_mask |= _PAGE_IOMAP; + /* + * Prevent page tables from being allocated in highmem, even + * if CONFIG_HIGHPTE is enabled. + */ + __userpte_alloc_gfp &= ~__GFP_HIGHMEM; + #ifdef CONFIG_X86_64 /* Work out if we support NX */ check_efer(); --- a/arch/x86/xen/mmu.c +++ b/arch/x86/xen/mmu.c @@ -1432,14 +1432,15 @@ static void *xen_kmap_atomic_pte(struct { pgprot_t prot = PAGE_KERNEL; + /* + * We disable highmem allocations for page tables so we should never + * see any calls to kmap_atomic_pte on a highmem page. + */ + BUG_ON(PageHighMem(page)); + if (PagePinned(page)) prot = PAGE_KERNEL_RO; - if (0 && PageHighMem(page)) - printk("mapping highpte %lx type %d prot %s\n", - page_to_pfn(page), type, - (unsigned long)pgprot_val(prot) & _PAGE_RW ? "WRITE" : "READ"); - return kmap_atomic_prot(page, type, prot); } #endif Patches currently in stable-queue which might be from ian.campbell@xxxxxxxxxx are _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-devel
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