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Gerd Hoffmann

2015-Jun-18 09:27 UTC

[PATCH v2] virtio-pci: alloc only resources actually used.

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 at redhat.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 | 66 +++++++++++++++++++++++++++++++++++++-
 4 files changed, 82 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..d9976ad 100644
--- a/drivers/virtio/virtio_pci_modern.c
+++ b/drivers/virtio/virtio_pci_modern.c
@@ -64,6 +64,37 @@ static void vp_iowrite64_twopart(u64 val,
 	vp_iowrite32(val >> 32, hi);
 }
 
+static struct resource *request_capability(struct pci_dev *dev, int off,
+					   int limit, 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);
+
+	if (offset + length < offset ||
+	    offset + length > pci_resource_len(dev, bar)) {
+		dev_err(&dev->dev,
+			"virtio_pci: virtio capability %u@%u "
+			"out of range on bar %i length %lu\n",
+			length, offset, bar,
+			(unsigned long)pci_resource_len(dev, bar));
+		return NULL;
+	}
+
+	if (limit && length > limit)
+		length = limit;
+
+	return request_mem_region(pci_resource_start(dev, bar) + offset,
+				  length, name);
+}
+
 static void __iomem *map_capability(struct pci_dev *dev, int off,
 				    size_t minlen,
 				    u32 align,
@@ -131,10 +162,12 @@ 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 +675,22 @@ 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, 0,
+						"virtio-pci-common");
+	vp_dev->res_isr = request_capability(pci_dev, isr, 0,
+						"virtio-pci-isr");
+	vp_dev->res_notify = request_capability(pci_dev, notify, 0,
+						"virtio-pci-notify");
+	if (device) {
+		vp_dev->res_device = request_capability(pci_dev, device,
+							PAGE_SIZE,
+							"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,
@@ -714,6 +763,15 @@ 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 +785,10 @@ 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

Michael S. Tsirkin

2015-Jun-18 09:58 UTC

head link

[PATCH v2] virtio-pci: alloc only resources actually used.

On Thu, Jun 18, 2015 at 11:27:34AM +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 at redhat.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 | 66
+++++++++++++++++++++++++++++++++++++-
>  4 files changed, 82 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..d9976ad 100644
> --- a/drivers/virtio/virtio_pci_modern.c
> +++ b/drivers/virtio/virtio_pci_modern.c
> @@ -64,6 +64,37 @@ static void vp_iowrite64_twopart(u64 val,
>  	vp_iowrite32(val >> 32, hi);
>  }
>  
> +static struct resource *request_capability(struct pci_dev *dev, int off,
> +					   int limit, 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);
> +
> +	if (offset + length < offset ||
> +	    offset + length > pci_resource_len(dev, bar)) {
> +		dev_err(&dev->dev,
> +			"virtio_pci: virtio capability %u@%u "
> +			"out of range on bar %i length %lu\n",
> +			length, offset, bar,
> +			(unsigned long)pci_resource_len(dev, bar));
> +		return NULL;
> +	}
> +
> +	if (limit && length > limit)
> +		length = limit;
> +
I'll have to review the above carefully. Hopefully next week.
Any reason you didn't just move code out map_capability to a helper,
without changes?  Would have made review easier.

I don't see reasons to request regions that we aren't going to
claim ...

> +	return request_mem_region(pci_resource_start(dev, bar) + offset,
> +				  length, name);
Hmm this seems wrong, resource can be IO, not just memory.
> +}
> +
>  static void __iomem *map_capability(struct pci_dev *dev, int off,
>  				    size_t minlen,
>  				    u32 align,
> @@ -131,10 +162,12 @@ 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 +675,22 @@ 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, 0,
Please make limit = sizeof(struct virtio_pci_common_cfg) and not 0.
> +						"virtio-pci-common");
> +	vp_dev->res_isr = request_capability(pci_dev, isr, 0,
> +						"virtio-pci-isr");
And here, 1.
> +	vp_dev->res_notify = request_capability(pci_dev, notify, 0,
> +						"virtio-pci-notify");
> +	if (device) {
> +		vp_dev->res_device = request_capability(pci_dev, device,
> +							PAGE_SIZE,
> +							"virtio-pci-device");
> +	}
Please drop {} around a single statement.
> +	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,
> @@ -714,6 +763,15 @@ 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 +785,10 @@ 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

Gerd Hoffmann

2015-Jun-18 10:33 UTC

head link

[PATCH v2] virtio-pci: alloc only resources actually used.

Hi,
> > +	if (offset + length < offset ||
> > +	    offset + length > pci_resource_len(dev, bar)) {
> > +		dev_err(&dev->dev,
> > +			"virtio_pci: virtio capability %u@%u "
> > +			"out of range on bar %i length %lu\n",
> > +			length, offset, bar,
> > +			(unsigned long)pci_resource_len(dev, bar));
> > +		return NULL;
> > +	}
> > +
> > +	if (limit && length > limit)
> > +		length = limit;
> > +
> 
> I'll have to review the above carefully. Hopefully next week.
> Any reason you didn't just move code out map_capability to a helper,
> without changes?  Would have made review easier.
Doesn't work that easily as there are different things to check.
request_capability verifies the capability itself only, map_capability
has a bunch of additional range checks because it supports partial maps.
> I don't see reasons to request regions that we aren't going to
> claim ...
I had it that way first, simply calling request_mem_region from
map_capability.  But then you get tons of notify entries in /proc/iomem,
and keeping track of the requested regions (for cleanup in
virtio_pci_modern_remove) also is more complicated than with a simple
set of 4 fixed regions.
> > +	return request_mem_region(pci_resource_start(dev, bar) + offset,
> > +				  length, name);
> 
> Hmm this seems wrong, resource can be IO, not just memory.
Right (not the case in the current qemu implementation, but still ...).
> > +	vp_dev->res_common = request_capability(pci_dev, common, 0,
> 
> Please make limit = sizeof(struct virtio_pci_common_cfg) and not 0.
> 
> > +						"virtio-pci-common");
> > +	vp_dev->res_isr = request_capability(pci_dev, isr, 0,
> > +						"virtio-pci-isr");
> 
> And here, 1.
> 
> > +	vp_dev->res_notify = request_capability(pci_dev, notify, 0,
> > +						"virtio-pci-notify");
> > +	if (device) {
> > +		vp_dev->res_device = request_capability(pci_dev, device,
> > +							PAGE_SIZE,
> > +							"virtio-pci-device");
> > +	}
> 
> Please drop {} around a single statement.
I'll fix them for the next version.

cheers,
  Gerd

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