From mboxrd@z Thu Jan 1 00:00:00 1970 From: julien.grall@citrix.com (Julien Grall) Date: Tue, 28 Jul 2015 16:02:44 +0100 Subject: [PATCH 3/8] arm/xen: implement correctly pfn_to_mfn In-Reply-To: <1438095769-2560-1-git-send-email-julien.grall@citrix.com> References: <1438095769-2560-1-git-send-email-julien.grall@citrix.com> Message-ID: <1438095769-2560-4-git-send-email-julien.grall@citrix.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org After the commit introducing convertion between DMA and guest address, all the callers of pfn_to_mfn are expecting to get a GFN (Guest Frame Number). On ARM, all the guests are auto-translated so the GFN is equal to the Linux PFN (Pseudo-physical Frame Number). The current implementation may return an MFN if the caller is passing a PFN associated to a mapped foreign grant. In pratical, I haven't seen the problem on running guest but we should fix it for the sake of correctness. Correct the implementation by always returning the pfn passed in parameter. A follow-up patch will take care to rename pfn_to_mfn to a suitable name. Signed-off-by: Julien Grall Cc: Stefano Stabellini Cc: Russell King Cc: linux-arm-kernel at lists.infradead.org --- arch/arm/include/asm/xen/page.h | 8 -------- 1 file changed, 8 deletions(-) diff --git a/arch/arm/include/asm/xen/page.h b/arch/arm/include/asm/xen/page.h index 6c9f6d2..493471f 100644 --- a/arch/arm/include/asm/xen/page.h +++ b/arch/arm/include/asm/xen/page.h @@ -36,14 +36,6 @@ extern struct rb_root phys_to_mach; static inline unsigned long pfn_to_mfn(unsigned long pfn) { - unsigned long mfn; - - if (phys_to_mach.rb_node != NULL) { - mfn = __pfn_to_mfn(pfn); - if (mfn != INVALID_P2M_ENTRY) - return mfn; - } - return pfn; } -- 2.1.4