Commit 0de58f85 authored Dec 03, 2015 by Ard Biesheuvel Committed by Marc Zyngier Dec 04, 2015

ARM/arm64: KVM: correct PTE uncachedness check



Commit e6fab544 ("ARM/arm64: KVM: test properly for a PTE's
uncachedness") modified the logic to test whether a HYP or stage-2
mapping needs flushing, from [incorrectly] interpreting the page table
attributes to [incorrectly] checking whether the PFN that backs the
mapping is covered by host system RAM. The PFN number is part of the
output of the translation, not the input, so we have to use pte_pfn()
on the contents of the PTE, not __phys_to_pfn() on the HYP virtual
address or stage-2 intermediate physical address.

Fixes: e6fab544 ("ARM/arm64: KVM: test properly for a PTE's uncachedness")
Cc: stable@vger.kernel.org
Tested-by: Pavel Fedin <p.fedin@samsung.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

parent f6be563a

arch/arm/kvm/mmu.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -218,7 +218,7 @@ static void unmap_ptes(struct kvm kvm, pmd_t pmd,
		kvm_tlb_flush_vmid_ipa(kvm, addr);

		/* No need to invalidate the cache for device mappings */
		if (!kvm_is_device_pfn(__phys_to_pfn(addr)))
		if (!kvm_is_device_pfn(pte_pfn(old_pte)))
		kvm_flush_dcache_pte(old_pte);

		put_page(virt_to_page(pte));
		@@ -310,7 +310,7 @@ static void stage2_flush_ptes(struct kvm kvm, pmd_t pmd,

		pte = pte_offset_kernel(pmd, addr);
		do {
		if (!pte_none(*pte) && !kvm_is_device_pfn(__phys_to_pfn(addr)))
		if (!pte_none(pte) && !kvm_is_device_pfn(pte_pfn(pte)))
		kvm_flush_dcache_pte(*pte);
		} while (pte++, addr += PAGE_SIZE, addr != end);
		}

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