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Message-ID: <20150616160052-mutt-send-email-mst@redhat.com>
Date: Tue, 16 Jun 2015 16:11:21 +0200
From: "Michael S. Tsirkin" <mst@...hat.com>
To: Gerd Hoffmann <kraxel@...hat.com>
Cc: "open list:VIRTIO CORE, NET..."
<virtualization@...ts.linux-foundation.org>,
open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] virtio-pci: alloc only resources actually used.
On Tue, Jun 16, 2015 at 03:57:52PM +0200, Gerd Hoffmann wrote:
> Move resource allocation from common code to legacy and modern code.
> Only request resources actually used, i.e. bar0 in legacy mode and
> the regions specified by capabilities in modern mode.
>
> Signed-off-by: Gerd Hoffmann <kraxel@...hat.com>
> ---
> drivers/virtio/virtio_pci_common.c | 7 -----
> drivers/virtio/virtio_pci_common.h | 5 ++++
> drivers/virtio/virtio_pci_legacy.c | 13 +++++++++-
> drivers/virtio/virtio_pci_modern.c | 52 +++++++++++++++++++++++++++++++++++++-
> 4 files changed, 68 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/virtio/virtio_pci_common.c b/drivers/virtio/virtio_pci_common.c
> index eba1b7a..327a121 100644
> --- a/drivers/virtio/virtio_pci_common.c
> +++ b/drivers/virtio/virtio_pci_common.c
> @@ -510,10 +510,6 @@ static int virtio_pci_probe(struct pci_dev *pci_dev,
> if (rc)
> goto err_enable_device;
>
> - rc = pci_request_regions(pci_dev, "virtio-pci");
> - if (rc)
> - goto err_request_regions;
> -
> if (force_legacy) {
> rc = virtio_pci_legacy_probe(vp_dev);
> /* Also try modern mode if we can't map BAR0 (no IO space). */
> @@ -543,8 +539,6 @@ err_register:
> else
> virtio_pci_modern_remove(vp_dev);
> err_probe:
> - pci_release_regions(pci_dev);
> -err_request_regions:
> pci_disable_device(pci_dev);
> err_enable_device:
> kfree(vp_dev);
> @@ -562,7 +556,6 @@ static void virtio_pci_remove(struct pci_dev *pci_dev)
> else
> virtio_pci_modern_remove(vp_dev);
>
> - pci_release_regions(pci_dev);
> pci_disable_device(pci_dev);
> }
>
> diff --git a/drivers/virtio/virtio_pci_common.h b/drivers/virtio/virtio_pci_common.h
> index 28ee4e5..9e744b8 100644
> --- a/drivers/virtio/virtio_pci_common.h
> +++ b/drivers/virtio/virtio_pci_common.h
> @@ -75,6 +75,11 @@ struct virtio_pci_device {
> /* Multiply queue_notify_off by this value. (non-legacy mode). */
> u32 notify_offset_multiplier;
>
> + struct resource *res_common;
> + struct resource *res_isr;
> + struct resource *res_device;
> + struct resource *res_notify;
> +
> /* Legacy only field */
> /* the IO mapping for the PCI config space */
> void __iomem *ioaddr;
> diff --git a/drivers/virtio/virtio_pci_legacy.c b/drivers/virtio/virtio_pci_legacy.c
> index 256a527..48bc979 100644
> --- a/drivers/virtio/virtio_pci_legacy.c
> +++ b/drivers/virtio/virtio_pci_legacy.c
> @@ -215,6 +215,7 @@ static const struct virtio_config_ops virtio_pci_config_ops = {
> int virtio_pci_legacy_probe(struct virtio_pci_device *vp_dev)
> {
> struct pci_dev *pci_dev = vp_dev->pci_dev;
> + int rc;
>
> /* We only own devices >= 0x1000 and <= 0x103f: leave the rest. */
> if (pci_dev->device < 0x1000 || pci_dev->device > 0x103f)
> @@ -226,9 +227,14 @@ int virtio_pci_legacy_probe(struct virtio_pci_device *vp_dev)
> return -ENODEV;
> }
>
> + rc = pci_request_region(pci_dev, 0, "virtio-pci-legacy");
> + if (rc)
> + return rc;
> +
> + rc = -ENOMEM;
> vp_dev->ioaddr = pci_iomap(pci_dev, 0, 0);
> if (!vp_dev->ioaddr)
> - return -ENOMEM;
> + goto err_iomap;
>
> vp_dev->isr = vp_dev->ioaddr + VIRTIO_PCI_ISR;
>
> @@ -246,6 +252,10 @@ int virtio_pci_legacy_probe(struct virtio_pci_device *vp_dev)
> vp_dev->del_vq = del_vq;
>
> return 0;
> +
> +err_iomap:
> + pci_release_region(pci_dev, 0);
> + return rc;
> }
>
> void virtio_pci_legacy_remove(struct virtio_pci_device *vp_dev)
> @@ -253,4 +263,5 @@ void virtio_pci_legacy_remove(struct virtio_pci_device *vp_dev)
> struct pci_dev *pci_dev = vp_dev->pci_dev;
>
> pci_iounmap(pci_dev, vp_dev->ioaddr);
> + pci_release_region(pci_dev, 0);
> }
> diff --git a/drivers/virtio/virtio_pci_modern.c b/drivers/virtio/virtio_pci_modern.c
> index e88e099..b4bd92b 100644
> --- a/drivers/virtio/virtio_pci_modern.c
> +++ b/drivers/virtio/virtio_pci_modern.c
> @@ -64,6 +64,24 @@ static void vp_iowrite64_twopart(u64 val,
> vp_iowrite32(val >> 32, hi);
> }
>
> +static struct resource *request_capability(struct pci_dev *dev, int off,
> + const char *name)
> +{
> + u8 bar;
> + u32 offset, length;
> +
> + pci_read_config_byte(dev, off + offsetof(struct virtio_pci_cap,
> + bar),
> + &bar);
> + pci_read_config_dword(dev, off + offsetof(struct virtio_pci_cap, offset),
> + &offset);
> + pci_read_config_dword(dev, off + offsetof(struct virtio_pci_cap, length),
> + &length);
> +
> + return request_mem_region(pci_resource_start(dev, bar) + offset,
> + length, name);
> +}
> +
For device config, this might request too much. The spec says:
The drivers SHOULD only map part of configuration structure large enough
for device operation.
I think you should limit this to PAGE_SIZE like we do for map_capability.
> static void __iomem *map_capability(struct pci_dev *dev, int off,
> size_t minlen,
> u32 align,
> @@ -131,10 +149,12 @@ static void __iomem *map_capability(struct pci_dev *dev, int off,
> }
>
> p = pci_iomap_range(dev, bar, offset, length);
> - if (!p)
> + if (!p) {
> dev_err(&dev->dev,
> "virtio_pci: unable to map virtio %u@%u on bar %i\n",
> length, offset, bar);
> + return NULL;
> + }
> return p;
> }
>
> @@ -642,6 +662,21 @@ int virtio_pci_modern_probe(struct virtio_pci_device *vp_dev)
> device = virtio_pci_find_capability(pci_dev, VIRTIO_PCI_CAP_DEVICE_CFG,
> IORESOURCE_IO | IORESOURCE_MEM);
>
> + vp_dev->res_common = request_capability(pci_dev, common,
> + "virtio-pci-common");
> + vp_dev->res_isr = request_capability(pci_dev, isr,
> + "virtio-pci-isr");
> + vp_dev->res_notify = request_capability(pci_dev, notify,
> + "virtio-pci-notify");
> + if (device) {
> + vp_dev->res_device = request_capability(pci_dev, device,
> + "virtio-pci-device");
> + }
> + err = -EINVAL;
> + if (!vp_dev->res_common || !vp_dev->res_isr || !vp_dev->res_notify ||
> + (device && !vp_dev->res_device))
> + goto err_reserve;
> +
> err = -EINVAL;
> vp_dev->common = map_capability(pci_dev, common,
> sizeof(struct virtio_pci_common_cfg), 4,
map_capability has a bunch of checks in place to validate the capability
structure. With request_capability called earlier, they are now done too
late.
> @@ -714,6 +749,15 @@ err_map_notify:
> err_map_isr:
> pci_iounmap(pci_dev, vp_dev->common);
> err_map_common:
> +err_reserve:
> + if (vp_dev->res_common)
> + release_resource(vp_dev->res_common);
> + if (vp_dev->res_isr)
> + release_resource(vp_dev->res_isr);
> + if (vp_dev->res_notify)
> + release_resource(vp_dev->res_notify);
> + if (vp_dev->res_device)
> + release_resource(vp_dev->res_device);
> return err;
> }
>
> @@ -727,4 +771,10 @@ void virtio_pci_modern_remove(struct virtio_pci_device *vp_dev)
> pci_iounmap(pci_dev, vp_dev->notify_base);
> pci_iounmap(pci_dev, vp_dev->isr);
> pci_iounmap(pci_dev, vp_dev->common);
> +
> + release_resource(vp_dev->res_common);
> + release_resource(vp_dev->res_isr);
> + release_resource(vp_dev->res_notify);
> + if (vp_dev->res_device)
> + release_resource(vp_dev->res_device);
> }
> --
> 1.8.3.1
--
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