Commit bf70e551 authored Feb 25, 2016 by Dexuan Cui Committed by Thomas Gleixner Feb 25, 2016

x86/mm: Fix slow_virt_to_phys() for X86_PAE again



"d1cd1210: x86, pageattr: Prevent overflow in slow_virt_to_phys() for
X86_PAE" was unintentionally removed by the recent "34437e67: x86/mm: Fix
slow_virt_to_phys() to handle large PAT bit".

And, the variable 'phys_addr' was defined as "unsigned long" by mistake -- it should
be "phys_addr_t".

As a result, Hyper-V network driver in 32-PAE Linux guest can't work again.

Fixes: commit 34437e67: "x86/mm: Fix slow_virt_to_phys() to handle large PAT bit"
Signed-off-by: Dexuan Cui <decui@microsoft.com>
Reviewed-by: Toshi Kani <toshi.kani@hpe.com>
Cc: olaf@aepfle.de
Cc: gregkh@linuxfoundation.org
Cc: jasowang@redhat.com
Cc: driverdev-devel@linuxdriverproject.org
Cc: linux-mm@kvack.org
Cc: apw@canonical.com
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: K. Y. Srinivasan <kys@microsoft.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Link: http://lkml.kernel.org/r/1456394292-9030-1-git-send-email-decui@microsoft.com


Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

parent 3d44d51b

arch/x86/mm/pageattr.c

+10 −4

Original line number	Diff line number	Diff line
		@@ -419,24 +419,30 @@ pmd_t *lookup_pmd_address(unsigned long address)
		phys_addr_t slow_virt_to_phys(void *__virt_addr)
		{
		unsigned long virt_addr = (unsigned long)__virt_addr;
		unsigned long phys_addr, offset;
		phys_addr_t phys_addr;
		unsigned long offset;
		enum pg_level level;
		pte_t *pte;

		pte = lookup_address(virt_addr, &level);
		BUG_ON(!pte);

		/*
		* pXX_pfn() returns unsigned long, which must be cast to phys_addr_t
		* before being left-shifted PAGE_SHIFT bits -- this trick is to
		* make 32-PAE kernel work correctly.
		*/
		switch (level) {
		case PG_LEVEL_1G:
		phys_addr = pud_pfn((pud_t )pte) << PAGE_SHIFT;
		phys_addr = (phys_addr_t)pud_pfn((pud_t )pte) << PAGE_SHIFT;
		offset = virt_addr & ~PUD_PAGE_MASK;
		break;
		case PG_LEVEL_2M:
		phys_addr = pmd_pfn((pmd_t )pte) << PAGE_SHIFT;
		phys_addr = (phys_addr_t)pmd_pfn((pmd_t )pte) << PAGE_SHIFT;
		offset = virt_addr & ~PMD_PAGE_MASK;
		break;
		default:
		phys_addr = pte_pfn(*pte) << PAGE_SHIFT;
		phys_addr = (phys_addr_t)pte_pfn(*pte) << PAGE_SHIFT;
		offset = virt_addr & ~PAGE_MASK;
		}

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