Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752331AbaJVNzL (ORCPT ); Wed, 22 Oct 2014 09:55:11 -0400 Received: from mail-ob0-f176.google.com ([209.85.214.176]:52166 "EHLO mail-ob0-f176.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751786AbaJVNzH (ORCPT ); Wed, 22 Oct 2014 09:55:07 -0400 MIME-Version: 1.0 X-Originating-IP: [2a01:e35:2434:4600:389c:cfae:9fd8:91b0] In-Reply-To: <1413909282.4202.141.camel@ul30vt.home> References: <1413205825-6370-1-git-send-email-a.motakis@virtualopensystems.com> <1413205825-6370-8-git-send-email-a.motakis@virtualopensystems.com> <1413909282.4202.141.camel@ul30vt.home> From: Antonios Motakis Date: Wed, 22 Oct 2014 15:54:46 +0200 Message-ID: Subject: Re: [PATCH v8 07/18] vfio/platform: return info for device memory mapped IO regions To: Alex Williamson Cc: kvm-arm , Linux IOMMU , Will Deacon , VirtualOpenSystems Technical Team , Christoffer Dall , Eric Auger , Kim Phillips , Marc Zyngier , "open list:VFIO DRIVER" , open list Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Oct 21, 2014 at 6:34 PM, Alex Williamson wrote: > On Mon, 2014-10-13 at 15:10 +0200, Antonios Motakis wrote: >> This patch enables the IOCTLs VFIO_DEVICE_GET_REGION_INFO ioctl call, >> which allows the user to learn about the available MMIO resources of >> a device. >> >> Signed-off-by: Antonios Motakis >> --- >> drivers/vfio/platform/vfio_platform_common.c | 93 +++++++++++++++++++++++++-- >> drivers/vfio/platform/vfio_platform_private.h | 22 +++++++ >> 2 files changed, 111 insertions(+), 4 deletions(-) >> >> diff --git a/drivers/vfio/platform/vfio_platform_common.c b/drivers/vfio/platform/vfio_platform_common.c >> index 1e4073f..8a7e474 100644 >> --- a/drivers/vfio/platform/vfio_platform_common.c >> +++ b/drivers/vfio/platform/vfio_platform_common.c >> @@ -27,17 +27,84 @@ >> >> #include "vfio_platform_private.h" >> >> +static int vfio_platform_regions_init(struct vfio_platform_device *vdev) >> +{ >> + int cnt = 0, i; >> + >> + while (vdev->get_resource(vdev, cnt)) >> + cnt++; >> + >> + vdev->regions = kcalloc(cnt, sizeof(struct vfio_platform_region), >> + GFP_KERNEL); >> + if (!vdev->regions) >> + return -ENOMEM; >> + >> + for (i = 0; i < cnt; i++) { >> + struct resource *res = >> + vdev->get_resource(vdev, i); >> + >> + if (!res) >> + goto err; >> + >> + vdev->regions[i].addr = res->start; >> + vdev->regions[i].size = resource_size(res); >> + vdev->regions[i].flags = 0; >> + >> + switch (resource_type(res)) { >> + case IORESOURCE_MEM: >> + vdev->regions[i].type = VFIO_PLATFORM_REGION_TYPE_MMIO; >> + break; >> + case IORESOURCE_IO: >> + vdev->regions[i].type = VFIO_PLATFORM_REGION_TYPE_PIO; >> + break; > > Ok, we have support for PIO in platform now (thanks!), does the user > know what type of region they're dealing with? Do they care? For PCI > the user tests the PCI BAR in config space to determine which type it > is. I'm guessing that platform would do something similar against the > device tree or ACPI, right? Maybe is worthwhile to add an explicit flag in VFIO_DEVICE_GET_REGION_INFO for PIO regions. For platform devices I don't know if we can always rely on DT or ACPI info to be available. For VFIO PCI the BAR is always implemented, and while I have proposed an RFC to return DT information, I don't think we can assume how a device is described in the host, whether DT, ACPI, or dark magic. > >> + default: >> + goto err; >> + } >> + } >> + >> + vdev->num_regions = cnt; >> + >> + return 0; >> +err: >> + kfree(vdev->regions); >> + return -EINVAL; >> +} >> + >> +static void vfio_platform_regions_cleanup(struct vfio_platform_device *vdev) >> +{ >> + vdev->num_regions = 0; >> + kfree(vdev->regions); >> +} >> + >> static void vfio_platform_release(void *device_data) >> { >> + struct vfio_platform_device *vdev = device_data; >> + >> + if (atomic_dec_and_test(&vdev->refcnt)) >> + vfio_platform_regions_cleanup(vdev); >> + >> module_put(THIS_MODULE); >> } >> >> static int vfio_platform_open(void *device_data) >> { >> + struct vfio_platform_device *vdev = device_data; >> + int ret; >> + >> if (!try_module_get(THIS_MODULE)) >> return -ENODEV; >> >> + if (atomic_inc_return(&vdev->refcnt) == 1) { >> + ret = vfio_platform_regions_init(vdev); >> + if (ret) >> + goto err_reg; >> + } >> + >> return 0; >> + >> +err_reg: >> + module_put(THIS_MODULE); >> + return ret; > > Note that if vfio_platform_regions_init() fails then your refcnt is > wrong. We switched to a mutex in vfio-pci to avoid this. See > 61d792562b53. Ack. > >> } >> >> static long vfio_platform_ioctl(void *device_data, >> @@ -58,15 +125,33 @@ static long vfio_platform_ioctl(void *device_data, >> return -EINVAL; >> >> info.flags = vdev->flags; >> - info.num_regions = 0; >> + info.num_regions = vdev->num_regions; >> info.num_irqs = 0; >> >> return copy_to_user((void __user *)arg, &info, minsz); >> >> - } else if (cmd == VFIO_DEVICE_GET_REGION_INFO) >> - return -EINVAL; >> + } else if (cmd == VFIO_DEVICE_GET_REGION_INFO) { >> + struct vfio_region_info info; >> + >> + minsz = offsetofend(struct vfio_region_info, offset); >> + >> + if (copy_from_user(&info, (void __user *)arg, minsz)) >> + return -EFAULT; >> + >> + if (info.argsz < minsz) >> + return -EINVAL; >> + >> + if (info.index >= vdev->num_regions) >> + return -EINVAL; >> + >> + /* map offset to the physical address */ >> + info.offset = VFIO_PLATFORM_INDEX_TO_OFFSET(info.index); >> + info.size = vdev->regions[info.index].size; >> + info.flags = vdev->regions[info.index].flags; >> + >> + return copy_to_user((void __user *)arg, &info, minsz); >> >> - else if (cmd == VFIO_DEVICE_GET_IRQ_INFO) >> + } else if (cmd == VFIO_DEVICE_GET_IRQ_INFO) >> return -EINVAL; >> >> else if (cmd == VFIO_DEVICE_SET_IRQS) >> diff --git a/drivers/vfio/platform/vfio_platform_private.h b/drivers/vfio/platform/vfio_platform_private.h >> index ef76737..2a06035 100644 >> --- a/drivers/vfio/platform/vfio_platform_private.h >> +++ b/drivers/vfio/platform/vfio_platform_private.h >> @@ -15,7 +15,29 @@ >> #ifndef VFIO_PLATFORM_PRIVATE_H >> #define VFIO_PLATFORM_PRIVATE_H >> >> +#define VFIO_PLATFORM_OFFSET_SHIFT 40 >> +#define VFIO_PLATFORM_OFFSET_MASK (((u64)(1) << VFIO_PLATFORM_OFFSET_SHIFT) - 1) >> + >> +#define VFIO_PLATFORM_OFFSET_TO_INDEX(off) \ >> + (off >> VFIO_PLATFORM_OFFSET_SHIFT) >> + >> +#define VFIO_PLATFORM_INDEX_TO_OFFSET(index) \ >> + ((u64)(index) << VFIO_PLATFORM_OFFSET_SHIFT) >> + >> +struct vfio_platform_region { >> + u64 addr; >> + resource_size_t size; >> + u32 flags; >> + u32 type; >> +#define VFIO_PLATFORM_REGION_TYPE_MMIO 1 >> +#define VFIO_PLATFORM_REGION_TYPE_PIO 2 >> +}; >> + >> struct vfio_platform_device { >> + struct vfio_platform_region *regions; >> + u32 num_regions; >> + atomic_t refcnt; >> + >> /* >> * These fields should be filled by the bus driver at binding time >> */ > > > -- Antonios Motakis Virtual Open Systems -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/