RE: [patch 33/39] PCI/MSI: Sanitize MSI-X checks

[Tian, Kevin]

> From: Thomas Gleixner 
> Sent: Friday, November 11, 2022 9:55 PM
> 
> @@ -785,7 +786,7 @@ int __pci_enable_msix_range(struct pci_d
>   return -ENOSPC;
>   }
> 
> - rc = __pci_enable_msix(dev, entries, nvec, affd, flags);
> + rc = msix_capability_init(dev, entries, nvec, affd);
>   if (rc == 0)
>   return nvec;
> 

The check in following lines doesn't make sense now:

if (rc < minvec)
return -ENOSPC;

Re: [patch 33/39] PCI/MSI: Sanitize MSI-X checks

[Jason Gunthorpe]

On Fri, Nov 11, 2022 at 02:55:07PM +0100, Thomas Gleixner wrote:
> There is no point in doing the same sanity checks over and over in a loop
> during MSI-X enablement. Put them in front of the loop and return early
> when they fail.
> 
> Signed-off-by: Thomas Gleixner 
> ---
>  drivers/pci/msi/msi.c |   67 
> +-
>  1 file changed, 34 insertions(+), 33 deletions(-)

> + /* PCI_IRQ_VIRTUAL is a horrible hack! */

New comment too :)

Reviewed-by: Jason Gunthorpe 

Jason

Re: [patch 33/39] PCI/MSI: Sanitize MSI-X checks

[Bjorn Helgaas]

On Fri, Nov 11, 2022 at 02:55:07PM +0100, Thomas Gleixner wrote:
> There is no point in doing the same sanity checks over and over in a loop
> during MSI-X enablement. Put them in front of the loop and return early
> when they fail.
> 
> Signed-off-by: Thomas Gleixner 

Acked-by: Bjorn Helgaas 

> ---
>  drivers/pci/msi/msi.c |   67 
> +-
>  1 file changed, 34 insertions(+), 33 deletions(-)
> 
> --- a/drivers/pci/msi/msi.c
> +++ b/drivers/pci/msi/msi.c
> @@ -721,47 +721,31 @@ static int msix_capability_init(struct p
>   return ret;
>  }
>  
> -static int __pci_enable_msix(struct pci_dev *dev, struct msix_entry *entries,
> -  int nvec, struct irq_affinity *affd, int flags)
> +static bool pci_msix_validate_entries(struct msix_entry *entries, int nvec, 
> int hwsize)
>  {
> - int nr_entries;
>   int i, j;
>  
> - if (!pci_msi_supported(dev, nvec) || dev->current_state != PCI_D0)
> - return -EINVAL;
> + if (!entries)
> + return true;
>  
> - nr_entries = pci_msix_vec_count(dev);
> - if (nr_entries < 0)
> - return nr_entries;
> - if (nvec > nr_entries && !(flags & PCI_IRQ_VIRTUAL))
> - return nr_entries;
> -
> - if (entries) {
> - /* Check for any invalid entries */
> - for (i = 0; i < nvec; i++) {
> - if (entries[i].entry >= nr_entries)
> - return -EINVAL; /* invalid entry */
> - for (j = i + 1; j < nvec; j++) {
> - if (entries[i].entry == entries[j].entry)
> - return -EINVAL; /* duplicate entry */
> - }
> + for (i = 0; i < nvec; i++) {
> + /* Entry within hardware limit? */
> + if (entries[i].entry >= hwsize)
> + return false;
> +
> + /* Check for duplicate entries */
> + for (j = i + 1; j < nvec; j++) {
> + if (entries[i].entry == entries[j].entry)
> + return false;
>   }
>   }
> -
> - /* Check whether driver already requested for MSI IRQ */
> - if (dev->msi_enabled) {
> - pci_info(dev, "can't enable MSI-X (MSI IRQ already 
> assigned)\n");
> - return -EINVAL;
> - }
> - return msix_capability_init(dev, entries, nvec, affd);
> + return true;
>  }
>  
> -int __pci_enable_msix_range(struct pci_dev *dev,
> - struct msix_entry *entries, int minvec,
> - int maxvec, struct irq_affinity *affd,
> - int flags)
> +int __pci_enable_msix_range(struct pci_dev *dev, struct msix_entry *entries, 
> int minvec,
> + int maxvec, struct irq_affinity *affd, int flags)
>  {
> - int rc, nvec = maxvec;
> + int hwsize, rc, nvec = maxvec;
>  
>   if (maxvec < minvec)
>   return -ERANGE;
> @@ -774,6 +758,23 @@ int __pci_enable_msix_range(struct pci_d
>   if (WARN_ON_ONCE(dev->msix_enabled))
>   return -EINVAL;
>  
> + if (!pci_msi_supported(dev, nvec) || dev->current_state != PCI_D0)
> + return -EINVAL;
> +
> + hwsize = pci_msix_vec_count(dev);
> + if (hwsize < 0)
> + return hwsize;
> +
> + if (!pci_msix_validate_entries(entries, nvec, hwsize))
> + return -EINVAL;
> +
> + /* PCI_IRQ_VIRTUAL is a horrible hack! */
> + if (nvec > hwsize && !(flags & PCI_IRQ_VIRTUAL))
> + nvec = hwsize;
> +
> + if (nvec < minvec)
> + return -ENOSPC;
> +
>   rc = pci_setup_msi_context(dev);
>   if (rc)
>   return rc;
> @@ -785,7 +786,7 @@ int __pci_enable_msix_range(struct pci_d
>   return -ENOSPC;
>   }
>  
> - rc = __pci_enable_msix(dev, entries, nvec, affd, flags);
> + rc = msix_capability_init(dev, entries, nvec, affd);
>   if (rc == 0)
>   return nvec;
>  
> 

[patch 33/39] PCI/MSI: Sanitize MSI-X checks

[Thomas Gleixner]

There is no point in doing the same sanity checks over and over in a loop
during MSI-X enablement. Put them in front of the loop and return early
when they fail.

Signed-off-by: Thomas Gleixner 
---
 drivers/pci/msi/msi.c |   67 +-
 1 file changed, 34 insertions(+), 33 deletions(-)

--- a/drivers/pci/msi/msi.c
+++ b/drivers/pci/msi/msi.c
@@ -721,47 +721,31 @@ static int msix_capability_init(struct p
return ret;
 }
 
-static int __pci_enable_msix(struct pci_dev *dev, struct msix_entry *entries,
-int nvec, struct irq_affinity *affd, int flags)
+static bool pci_msix_validate_entries(struct msix_entry *entries, int nvec, 
int hwsize)
 {
-   int nr_entries;
int i, j;
 
-   if (!pci_msi_supported(dev, nvec) || dev->current_state != PCI_D0)
-   return -EINVAL;
+   if (!entries)
+   return true;
 
-   nr_entries = pci_msix_vec_count(dev);
-   if (nr_entries < 0)
-   return nr_entries;
-   if (nvec > nr_entries && !(flags & PCI_IRQ_VIRTUAL))
-   return nr_entries;
-
-   if (entries) {
-   /* Check for any invalid entries */
-   for (i = 0; i < nvec; i++) {
-   if (entries[i].entry >= nr_entries)
-   return -EINVAL; /* invalid entry */
-   for (j = i + 1; j < nvec; j++) {
-   if (entries[i].entry == entries[j].entry)
-   return -EINVAL; /* duplicate entry */
-   }
+   for (i = 0; i < nvec; i++) {
+   /* Entry within hardware limit? */
+   if (entries[i].entry >= hwsize)
+   return false;
+
+   /* Check for duplicate entries */
+   for (j = i + 1; j < nvec; j++) {
+   if (entries[i].entry == entries[j].entry)
+   return false;
}
}
-
-   /* Check whether driver already requested for MSI IRQ */
-   if (dev->msi_enabled) {
-   pci_info(dev, "can't enable MSI-X (MSI IRQ already 
assigned)\n");
-   return -EINVAL;
-   }
-   return msix_capability_init(dev, entries, nvec, affd);
+   return true;
 }
 
-int __pci_enable_msix_range(struct pci_dev *dev,
-   struct msix_entry *entries, int minvec,
-   int maxvec, struct irq_affinity *affd,
-   int flags)
+int __pci_enable_msix_range(struct pci_dev *dev, struct msix_entry *entries, 
int minvec,
+   int maxvec, struct irq_affinity *affd, int flags)
 {
-   int rc, nvec = maxvec;
+   int hwsize, rc, nvec = maxvec;
 
if (maxvec < minvec)
return -ERANGE;
@@ -774,6 +758,23 @@ int __pci_enable_msix_range(struct pci_d
if (WARN_ON_ONCE(dev->msix_enabled))
return -EINVAL;
 
+   if (!pci_msi_supported(dev, nvec) || dev->current_state != PCI_D0)
+   return -EINVAL;
+
+   hwsize = pci_msix_vec_count(dev);
+   if (hwsize < 0)
+   return hwsize;
+
+   if (!pci_msix_validate_entries(entries, nvec, hwsize))
+   return -EINVAL;
+
+   /* PCI_IRQ_VIRTUAL is a horrible hack! */
+   if (nvec > hwsize && !(flags & PCI_IRQ_VIRTUAL))
+   nvec = hwsize;
+
+   if (nvec < minvec)
+   return -ENOSPC;
+
rc = pci_setup_msi_context(dev);
if (rc)
return rc;
@@ -785,7 +786,7 @@ int __pci_enable_msix_range(struct pci_d
return -ENOSPC;
}
 
-   rc = __pci_enable_msix(dev, entries, nvec, affd, flags);
+   rc = msix_capability_init(dev, entries, nvec, affd);
if (rc == 0)
return nvec;