From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx0a-001b2d01.pphosted.com (mx0b-001b2d01.pphosted.com [148.163.158.5]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 3t3gj506D3zDt2G for ; Wed, 26 Oct 2016 17:53:44 +1100 (AEDT) Received: from pps.filterd (m0098420.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.16.0.17/8.16.0.17) with SMTP id u9Q6qRs1083651 for ; Wed, 26 Oct 2016 02:53:42 -0400 Received: from e18.ny.us.ibm.com (e18.ny.us.ibm.com [129.33.205.208]) by mx0b-001b2d01.pphosted.com with ESMTP id 26aqkt8203-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Wed, 26 Oct 2016 02:53:42 -0400 Received: from localhost by e18.ny.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Wed, 26 Oct 2016 02:53:41 -0400 From: Yongji Xie To: bhelgaas@google.com Cc: linux-pci@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, alex.williamson@redhat.com, paulus@samba.org, aik@ozlabs.ru, gwshan@linux.vnet.ibm.com, benh@kernel.crashing.org, mpe@ellerman.id.au, zhong@linux.vnet.ibm.com Subject: [RFC PATCH v7 3/3] PCI: Add a macro to set default alignment for all PCI devices Date: Wed, 26 Oct 2016 14:53:33 +0800 In-Reply-To: <1477464813-2499-1-git-send-email-xyjxie@linux.vnet.ibm.com> References: <1477464813-2499-1-git-send-email-xyjxie@linux.vnet.ibm.com> Message-Id: <1477464813-2499-4-git-send-email-xyjxie@linux.vnet.ibm.com> List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , When vfio passthroughs a PCI device of which MMIO BARs are smaller than PAGE_SIZE, guest will not handle the mmio accesses to the BARs which leads to mmio emulations in host. This is because vfio will not allow to passthrough one BAR's mmio page which may be shared with other BARs. Otherwise, there will be a backdoor that guest can use to access BARs of other guest. This patch adds a macro to set default alignment for all PCI devices. Then we could solve this issue on some platforms which would easily hit this issue because of their 64K page such as PowerNV platform by defining this macro as PAGE_SIZE. Signed-off-by: Yongji Xie --- arch/powerpc/include/asm/pci.h | 4 ++++ drivers/pci/pci.c | 3 +++ 2 files changed, 7 insertions(+) diff --git a/arch/powerpc/include/asm/pci.h b/arch/powerpc/include/asm/pci.h index e9bd6cf..5e31bc2 100644 --- a/arch/powerpc/include/asm/pci.h +++ b/arch/powerpc/include/asm/pci.h @@ -28,6 +28,10 @@ #define PCIBIOS_MIN_IO 0x1000 #define PCIBIOS_MIN_MEM 0x10000000 +#ifdef CONFIG_PPC_POWERNV +#define PCIBIOS_DEFAULT_ALIGNMENT PAGE_SIZE +#endif + struct pci_dev; /* Values for the `which' argument to sys_pciconfig_iobase syscall. */ diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index 2933c81..c7d9057 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -4999,6 +4999,9 @@ static resource_size_t pci_specified_resource_alignment(struct pci_dev *dev) resource_size_t align = 0; char *p; +#ifdef PCIBIOS_DEFAULT_ALIGNMENT + align = PCIBIOS_DEFAULT_ALIGNMENT; +#endif spin_lock(&resource_alignment_lock); p = resource_alignment_param; if (!*p) -- 1.7.9.5