linux-kernel - [PATCH 6/9] x86/xen: do not use _PAGE_IOMAP in xen_remap_domain_mfn

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Date:	Tue, 15 Apr 2014 15:15:34 +0100
From:	David Vrabel <david.vrabel@...rix.com>
To:	<xen-devel@...ts.xenproject.org>
CC:	Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>,
	Boris Ostrovsky <boris.ostrovsky@...cle.com>,
	David Vrabel <david.vrabel@...rix.com>,
	<linux-kernel@...r.kernel.org>,
	Thomas Gleixner <tglx@...utronix.de>,
	"Ingo Molnar" <mingo@...hat.com>, "H. Peter Anvin" <hpa@...or.com>,
	<x86@...nel.org>, Mel Gorman <mgorman@...e.de>
Subject: [PATCH 6/9] x86/xen: do not use _PAGE_IOMAP in xen_remap_domain_mfn_range()

_PAGE_IOMAP is used in xen_remap_domain_mfn_range() to prevent the
pfn_pte() call in remap_area_mfn_pte_fn() from using the p2m to translate
the MFN.  If mfn_pte() is used instead, the p2m look up is avoided and
the use of _PAGE_IOMAP is no longer needed.

Signed-off-by: David Vrabel <david.vrabel@...rix.com>
---
 arch/x86/xen/mmu.c |    4 +---
 1 files changed, 1 insertions(+), 3 deletions(-)

diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c
index 86e02ea..d916024 100644
--- a/arch/x86/xen/mmu.c
+++ b/arch/x86/xen/mmu.c
@@ -2522,7 +2522,7 @@ static int remap_area_mfn_pte_fn(pte_t *ptep, pgtable_t token,
 				 unsigned long addr, void *data)
 {
 	struct remap_data *rmd = data;
-	pte_t pte = pte_mkspecial(pfn_pte(rmd->mfn++, rmd->prot));
+	pte_t pte = pte_mkspecial(mfn_pte(rmd->mfn++, rmd->prot));
 
 	rmd->mmu_update->ptr = virt_to_machine(ptep).maddr;
 	rmd->mmu_update->val = pte_val_ma(pte);
@@ -2547,8 +2547,6 @@ int xen_remap_domain_mfn_range(struct vm_area_struct *vma,
 	if (xen_feature(XENFEAT_auto_translated_physmap))
 		return -EINVAL;
 
-	prot = __pgprot(pgprot_val(prot) | _PAGE_IOMAP);
-
 	BUG_ON(!((vma->vm_flags & (VM_PFNMAP | VM_IO)) == (VM_PFNMAP | VM_IO)));
 
 	rmd.mfn = mfn;
-- 
1.7.2.5

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