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Commit 500dd237 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'stable/for-linus-fixes-3.3-rc5' of... 

Merge tag 'stable/for-linus-fixes-3.3-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen



Two fixes to fix a memory corruption bug when WC pages never get
converted back to WB but end up being recycled in the general memory
pool as WC.

There is a better way of fixing this, but there is not enough time to do
the full benchmarking to pick one of the right options - so picking the
one that favors stability for right now.

Signed-off-by: default avatarKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

* tag 'stable/for-linus-fixes-3.3-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen:
  xen/pat: Disable PAT support for now.
  xen/setup: Remove redundant filtering of PTE masks.
parents f6bd5798 8eaffa67

arch/x86/xen/enlighten.c

+2 −4
Original line number Diff line number Diff line
@@ -1141,7 +1141,9 @@ asmlinkage void __init xen_start_kernel(void) 


	/* Prevent unwanted bits from being set in PTEs. */

	__supported_pte_mask &= ~_PAGE_GLOBAL;

#if 0

	if (!xen_initial_domain())

#endif

		__supported_pte_mask &= ~(_PAGE_PWT | _PAGE_PCD);



	__supported_pte_mask |= _PAGE_IOMAP;
@@ -1204,10 +1206,6 @@ asmlinkage void __init xen_start_kernel(void) 


	pgd = (pgd_t *)xen_start_info->pt_base;



	if (!xen_initial_domain())

		__supported_pte_mask &= ~(_PAGE_PWT | _PAGE_PCD);



	__supported_pte_mask |= _PAGE_IOMAP;

	/* Don't do the full vcpu_info placement stuff until we have a

	   possible map and a non-dummy shared_info. */

	per_cpu(xen_vcpu, 0) = &HYPERVISOR_shared_info->vcpu_info[0];

arch/x86/xen/mmu.c

+4 −4
Original line number Diff line number Diff line
@@ -415,13 +415,13 @@ static pteval_t iomap_pte(pteval_t val) 
static pteval_t xen_pte_val(pte_t pte)

{

	pteval_t pteval = pte.pte;



#if 0

	/* If this is a WC pte, convert back from Xen WC to Linux WC */

	if ((pteval & (_PAGE_PAT | _PAGE_PCD | _PAGE_PWT)) == _PAGE_PAT) {

		WARN_ON(!pat_enabled);

		pteval = (pteval & ~_PAGE_PAT) | _PAGE_PWT;

	}



#endif

	if (xen_initial_domain() && (pteval & _PAGE_IOMAP))

		return pteval;
@@ -463,7 +463,7 @@ void xen_set_pat(u64 pat) 
static pte_t xen_make_pte(pteval_t pte)

{

	phys_addr_t addr = (pte & PTE_PFN_MASK);



#if 0

	/* If Linux is trying to set a WC pte, then map to the Xen WC.

	 * If _PAGE_PAT is set, then it probably means it is really

	 * _PAGE_PSE, so avoid fiddling with the PAT mapping and hope
@@ -476,7 +476,7 @@ static pte_t xen_make_pte(pteval_t pte) 
		if ((pte & (_PAGE_PCD | _PAGE_PWT)) == _PAGE_PWT)

			pte = (pte & ~(_PAGE_PCD | _PAGE_PWT)) | _PAGE_PAT;

	}



#endif

	/*

	 * Unprivileged domains are allowed to do IOMAPpings for

	 * PCI passthrough, but not map ISA space.  The ISA