| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-Id: <86cda5cf2742feff3b14954284fb509863355050.1681837892.git.reinette.chatre@intel.com>
Date: Tue, 18 Apr 2023 10:29:20 -0700
From: Reinette Chatre <reinette.chatre@...el.com>
To: jgg@...dia.com, yishaih@...dia.com,
shameerali.kolothum.thodi@...wei.com, kevin.tian@...el.com,
alex.williamson@...hat.com
Cc: tglx@...utronix.de, darwi@...utronix.de, kvm@...r.kernel.org,
dave.jiang@...el.com, jing2.liu@...el.com, ashok.raj@...el.com,
fenghua.yu@...el.com, tom.zanussi@...ux.intel.com,
reinette.chatre@...el.com, linux-kernel@...r.kernel.org
Subject: [PATCH V3 09/10] vfio/pci: Support dynamic MSI-X
Recently introduced pci_msix_alloc_irq_at() and pci_msix_free_irq()
enables an individual MSI-X interrupt to be allocated and freed after
MSI-X enabling.
Use dynamic MSI-X (if supported by the device) to allocate an interrupt
after MSI-X is enabled. An MSI-X interrupt is dynamically allocated at
the time a valid eventfd is assigned. This is different behavior from
a range provided during MSI-X enabling where interrupts are allocated
for the entire range whether a valid eventfd is provided for each
interrupt or not.
Do not dynamically free interrupts, leave that to when MSI-X is
disabled.
Signed-off-by: Reinette Chatre <reinette.chatre@...el.com>
Link: https://lore.kernel.org/lkml/20230403211841.0e206b67.alex.williamson@redhat.com/
---
The get_cached_msi_msg()/pci_write_msi_msg() behavior is kept
similar to the scenario when MSI-X is enabled with triggers
provided for new interrupts. get_cached_msi_msg()/pci_write_msi_msg()
follows for interrupts recently allocated with pci_msix_alloc_irq_at()
just like get_cached_msi_msg()/pci_write_msi_msg() is done for
interrupts recently allocated with pci_alloc_irq_vectors().
Changes since V2:
- Move vfio_irq_ctx_free() to earlier in series to support
earlier usage. (Alex)
- Use consistent terms in changelog: MSI-x changed to MSI-X.
- Make dynamic interrupt context creation generic across all
MSI/MSI-X interrupts. This resulted in code moving to earlier
in series as part of xarray introduction patch. (Alex)
- Remove the local allow_dyn_alloc and direct calling of
pci_msix_can_alloc_dyn(), use the new vdev->has_dyn_msix
introduced earlier instead. (Alex)
- Stop tracking new allocations (remove "new_ctx"). (Alex)
- Introduce new wrapper that returns Linux interrupt number or
dynamically allocate a new interrupt. Wrapper can be used for
all interrupt cases. (Alex)
- Only free dynamic MSI-X interrupts on MSI-X teardown. (Alex)
Changes since RFC V1:
- Add pointer to interrupt context as function parameter to
vfio_irq_ctx_free(). (Alex)
- Initialize new_ctx to false. (Dan Carpenter)
- Only support dynamic allocation if device supports it. (Alex)
drivers/vfio/pci/vfio_pci_intrs.c | 73 +++++++++++++++++++++++++++----
1 file changed, 65 insertions(+), 8 deletions(-)
diff --git a/drivers/vfio/pci/vfio_pci_intrs.c b/drivers/vfio/pci/vfio_pci_intrs.c
index bdda7f46c2be..c1a3e224c867 100644
--- a/drivers/vfio/pci/vfio_pci_intrs.c
+++ b/drivers/vfio/pci/vfio_pci_intrs.c
@@ -372,27 +372,74 @@ static int vfio_msi_enable(struct vfio_pci_core_device *vdev, int nvec, bool msi
return 0;
}
+/*
+ * Return Linux IRQ number of an MSI or MSI-X device interrupt vector.
+ * If a Linux IRQ number is not available then a new interrupt will be
+ * allocated if dynamic MSI-X is supported.
+ */
+static int vfio_msi_alloc_irq(struct vfio_pci_core_device *vdev,
+ unsigned int vector, bool msix)
+{
+ struct pci_dev *pdev = vdev->pdev;
+ struct msi_map map;
+ int irq;
+ u16 cmd;
+
+ irq = pci_irq_vector(pdev, vector);
+ if (irq > 0 || !msix || !vdev->has_dyn_msix)
+ return irq;
+
+ cmd = vfio_pci_memory_lock_and_enable(vdev);
+ map = pci_msix_alloc_irq_at(pdev, vector, NULL);
+ vfio_pci_memory_unlock_and_restore(vdev, cmd);
+
+ return map.index < 0 ? map.index : map.virq;
+}
+
+/*
+ * Free interrupt if it can be re-allocated dynamically (while MSI-X
+ * is enabled).
+ */
+static void vfio_msi_free_irq(struct vfio_pci_core_device *vdev,
+ unsigned int vector, bool msix)
+{
+ struct pci_dev *pdev = vdev->pdev;
+ struct msi_map map;
+ int irq;
+ u16 cmd;
+
+ if (!msix || !vdev->has_dyn_msix)
+ return;
+
+ irq = pci_irq_vector(pdev, vector);
+ map = (struct msi_map) { .index = vector, .virq = irq };
+
+ if (WARN_ON(irq < 0))
+ return;
+
+ cmd = vfio_pci_memory_lock_and_enable(vdev);
+ pci_msix_free_irq(pdev, map);
+ vfio_pci_memory_unlock_and_restore(vdev, cmd);
+}
+
static int vfio_msi_set_vector_signal(struct vfio_pci_core_device *vdev,
unsigned int vector, int fd, bool msix)
{
struct pci_dev *pdev = vdev->pdev;
struct vfio_pci_irq_ctx *ctx;
struct eventfd_ctx *trigger;
- int irq, ret;
+ int irq = -EINVAL, ret;
u16 cmd;
- irq = pci_irq_vector(pdev, vector);
- if (irq < 0)
- return -EINVAL;
-
ctx = vfio_irq_ctx_get(vdev, vector);
if (ctx) {
irq_bypass_unregister_producer(&ctx->producer);
-
+ irq = pci_irq_vector(pdev, vector);
cmd = vfio_pci_memory_lock_and_enable(vdev);
free_irq(irq, ctx->trigger);
vfio_pci_memory_unlock_and_restore(vdev, cmd);
+ /* Interrupt stays allocated, will be freed at MSI-X disable. */
kfree(ctx->name);
eventfd_ctx_put(ctx->trigger);
vfio_irq_ctx_free(vdev, ctx, vector);
@@ -401,9 +448,17 @@ static int vfio_msi_set_vector_signal(struct vfio_pci_core_device *vdev,
if (fd < 0)
return 0;
+ if (irq == -EINVAL) {
+ irq = vfio_msi_alloc_irq(vdev, vector, msix);
+ if (irq < 0)
+ return irq;
+ }
+
ctx = vfio_irq_ctx_alloc(vdev, vector);
- if (!ctx)
- return -ENOMEM;
+ if (!ctx) {
+ ret = -ENOMEM;
+ goto out_free_irq;
+ }
ctx->name = kasprintf(GFP_KERNEL_ACCOUNT, "vfio-msi%s[%d](%s)",
msix ? "x" : "", vector, pci_name(pdev));
@@ -456,6 +511,8 @@ static int vfio_msi_set_vector_signal(struct vfio_pci_core_device *vdev,
kfree(ctx->name);
out_free_ctx:
vfio_irq_ctx_free(vdev, ctx, vector);
+out_free_irq:
+ vfio_msi_free_irq(vdev, vector, msix);
return ret;
}
--
2.34.1
Powered by blists - more mailing lists