From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alejandro Lucero Subject: Re: [dpdk-stable] [PATCH v3 3/6] bus/pci: use IOVAs check when setting IOVA mode Date: Tue, 10 Jul 2018 16:37:08 +0100 Message-ID: References: <1530708838-2682-1-git-send-email-alejandro.lucero@netronome.com> <1530708838-2682-4-git-send-email-alejandro.lucero@netronome.com> <79AD128F-0B7B-49B6-8F20-3C9A72036769@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Cc: dev , stable@dpdk.org, "Burakov, Anatoly" , Maxime Coquelin , Ferruh Yigit To: Eelco Chaudron Return-path: Received: from mail-ed1-f68.google.com (mail-ed1-f68.google.com [209.85.208.68]) by dpdk.org (Postfix) with ESMTP id 7DDD41B455 for ; Tue, 10 Jul 2018 17:37:09 +0200 (CEST) Received: by mail-ed1-f68.google.com with SMTP id d17-v6so4829274eds.11 for ; Tue, 10 Jul 2018 08:37:09 -0700 (PDT) In-Reply-To: <79AD128F-0B7B-49B6-8F20-3C9A72036769@redhat.com> List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Sender: "dev" On Tue, Jul 10, 2018 at 11:14 AM, Eelco Chaudron wrote: > > > On 4 Jul 2018, at 14:53, Alejandro Lucero wrote: > > Although VT-d emulation currently only supports 39 bits, it could >> be iovas being within that supported range. This patch allows >> IOVA mode in such a case. >> >> Indeed, memory initialization code can be modified for using lower >> virtual addresses than those used by the kernel for 64 bits processes >> by default, and therefore memsegs iovas can use 39 bits or less for >> most system. And this is likely 100% true for VMs. >> >> Signed-off-by: Alejandro Lucero >> --- >> drivers/bus/pci/linux/pci.c | 15 +++++++++++---- >> 1 file changed, 11 insertions(+), 4 deletions(-) >> >> diff --git a/drivers/bus/pci/linux/pci.c b/drivers/bus/pci/linux/pci.c >> index 74deef3..792c819 100644 >> --- a/drivers/bus/pci/linux/pci.c >> +++ b/drivers/bus/pci/linux/pci.c >> @@ -43,6 +43,7 @@ >> #include >> #include >> #include >> +#include >> >> #include "eal_private.h" >> #include "eal_filesystem.h" >> @@ -613,10 +614,12 @@ >> fclose(fp); >> >> mgaw = ((vtd_cap_reg & VTD_CAP_MGAW_MASK) >> VTD_CAP_MGAW_SHIFT) >> + 1; >> - if (mgaw < X86_VA_WIDTH) >> + >> + if (!rte_eal_check_dma_mask(mgaw)) >> > > If think in this case we still need to check the X86_VA_WIDTH, i.e. > if (mgaw < X86_VA_WIDTH && !rte_eal_check_dma_mask(mgaw)) > > > + return true; >> + else >> return false; >> >> - return true; >> } >> #elif defined(RTE_ARCH_PPC_64) >> static bool >> @@ -640,13 +643,17 @@ >> { >> struct rte_pci_device *dev = NULL; >> struct rte_pci_driver *drv = NULL; >> + int iommu_dma_mask_check_done = 0; >> >> FOREACH_DRIVER_ON_PCIBUS(drv) { >> FOREACH_DEVICE_ON_PCIBUS(dev) { >> if (!rte_pci_match(drv, dev)) >> continue; >> - if (!pci_one_device_iommu_support_va(dev)) >> - return false; >> + if (!iommu_dma_mask_check_done) { >> + if (pci_one_device_iommu_support_va(dev) >> < 0) >> + return false; >> + iommu_dma_mask_check_done = 1; >> > > Not sure why this change? Why do we only need to check one device on the > bus? > > Because there is just one emulated IOMMU hardware. The limitation in this case is not in a specific PCI device. And I do not think it is possible to have two different (emulated or not) IOMMU hardware. Yes, you can have more than one controller but being same IOMMU type. > In addition, if this is what was intended, rather than a variable you can > return true in this case, or did you intended to clear the > iommu_dma_mask_check_done on every PCI BUS iteration? > > If pci_one_device_iommu_support_va, because the dma check, finds out the IOVAs are out of range, then the IOVA mode is PA and no further checks are required. But there could be a PCI device precluding the IOVA VA, so all the PCI devices need to be processed. > + } >> } >> } >> return true; >> -- >> 1.9.1 >> >