2022-11-11 16:09:01

by Thomas Gleixner

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

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 <[email protected]>
---
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;

2022-11-16 16:54:28

by Bjorn Helgaas

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

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 <[email protected]>

Acked-by: Bjorn Helgaas <[email protected]>

> ---
> 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;
>
>

2022-11-16 18:45:14

by Jason Gunthorpe

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

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 <[email protected]>
> ---
> 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 <[email protected]>

Jason

2022-11-17 15:22:11

by tip-bot2 for Alexey Makhalov

Subject: [tip: irq/core] PCI/MSI: Sanitize MSI-X checks

The following commit has been merged into the irq/core branch of tip:

Commit-ID: bab65e48cb064d67b488efb6888c06fd977a8245
Gitweb: https://git.kernel.org/tip/bab65e48cb064d67b488efb6888c06fd977a8245
Author: Thomas Gleixner <[email protected]>
AuthorDate: Fri, 11 Nov 2022 14:55:07 +01:00
Committer: Thomas Gleixner <[email protected]>
CommitterDate: Thu, 17 Nov 2022 15:15:22 +01:00

PCI/MSI: Sanitize MSI-X checks

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 <[email protected]>
Reviewed-by: Jason Gunthorpe <[email protected]>
Acked-by: Bjorn Helgaas <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

---
drivers/pci/msi/msi.c | 65 +++++++++++++++++++++---------------------
1 file changed, 33 insertions(+), 32 deletions(-)

diff --git a/drivers/pci/msi/msi.c b/drivers/pci/msi/msi.c
index 380e651..794ec97 100644
--- a/drivers/pci/msi/msi.c
+++ b/drivers/pci/msi/msi.c
@@ -721,47 +721,31 @@ out_disable:
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;
+ for (i = 0; i < nvec; i++) {
+ /* Entry within hardware limit? */
+ if (entries[i].entry >= hwsize)
+ return false;

- 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 */
- }
+ /* 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_dev *dev,
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_dev *dev,
return -ENOSPC;
}

- rc = __pci_enable_msix(dev, entries, nvec, affd, flags);
+ rc = msix_capability_init(dev, entries, nvec, affd);
if (rc == 0)
return nvec;

2022-11-18 08:13:59

by Tian, Kevin

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

> From: Thomas Gleixner <[email protected]>
> 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;