| 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: <9f6caaedc278fe057aacb813d94f44a93d8cab3c.1763512374.git.nicolinc@nvidia.com>
Date: Tue, 18 Nov 2025 16:52:11 -0800
From: Nicolin Chen <nicolinc@...dia.com>
To: <robin.murphy@....com>, <joro@...tes.org>, <afael@...nel.org>,
<bhelgaas@...gle.com>, <alex@...zbot.org>, <jgg@...dia.com>,
<kevin.tian@...el.com>
CC: <will@...nel.org>, <lenb@...nel.org>, <baolu.lu@...ux.intel.com>,
<linux-arm-kernel@...ts.infradead.org>, <iommu@...ts.linux.dev>,
<linux-kernel@...r.kernel.org>, <linux-acpi@...r.kernel.org>,
<linux-pci@...r.kernel.org>, <kvm@...r.kernel.org>,
<patches@...ts.linux.dev>, <pjaroszynski@...dia.com>, <vsethi@...dia.com>,
<helgaas@...nel.org>, <etzhao1900@...il.com>
Subject: [PATCH v6 5/5] PCI: Suspend iommu function prior to resetting a device
PCIe permits a device to ignore ATS invalidation TLPs while processing a
reset. This creates a problem visible to the OS where an ATS invalidation
command will time out: e.g. an SVA domain will have no coordination with a
reset event and can racily issue ATS invalidations to a resetting device.
The PCIe r6.0, sec 10.3.1 IMPLEMENTATION NOTE recommends SW to disable and
block ATS before initiating a Function Level Reset. It also mentions that
other reset methods could have the same vulnerability as well.
The IOMMU subsystem provides pci_dev_reset_iommu_prepare/done() callback
helpers for this matter. Use them in all the existing reset functions.
This will attach the device to its iommu_group->blocking_domain during the
device reset, so as to allow IOMMU driver to:
- invoke pci_disable_ats() and pci_enable_ats(), if necessary
- wait for all ATS invalidations to complete
- stop issuing new ATS invalidations
- fence any incoming ATS queries
Signed-off-by: Nicolin Chen <nicolinc@...dia.com>
---
drivers/pci/pci-acpi.c | 13 +++++++--
drivers/pci/pci.c | 65 +++++++++++++++++++++++++++++++++++++-----
drivers/pci/quirks.c | 19 +++++++++++-
3 files changed, 87 insertions(+), 10 deletions(-)
diff --git a/drivers/pci/pci-acpi.c b/drivers/pci/pci-acpi.c
index 9369377725fa0..651d9b5561fff 100644
--- a/drivers/pci/pci-acpi.c
+++ b/drivers/pci/pci-acpi.c
@@ -9,6 +9,7 @@
#include <linux/delay.h>
#include <linux/init.h>
+#include <linux/iommu.h>
#include <linux/irqdomain.h>
#include <linux/pci.h>
#include <linux/msi.h>
@@ -971,6 +972,7 @@ void pci_set_acpi_fwnode(struct pci_dev *dev)
int pci_dev_acpi_reset(struct pci_dev *dev, bool probe)
{
acpi_handle handle = ACPI_HANDLE(&dev->dev);
+ int ret;
if (!handle || !acpi_has_method(handle, "_RST"))
return -ENOTTY;
@@ -978,12 +980,19 @@ int pci_dev_acpi_reset(struct pci_dev *dev, bool probe)
if (probe)
return 0;
+ ret = pci_dev_reset_iommu_prepare(dev);
+ if (ret) {
+ pci_err(dev, "failed to stop IOMMU for a PCI reset: %d\n", ret);
+ return ret;
+ }
+
if (ACPI_FAILURE(acpi_evaluate_object(handle, "_RST", NULL, NULL))) {
pci_warn(dev, "ACPI _RST failed\n");
- return -ENOTTY;
+ ret = -ENOTTY;
}
- return 0;
+ pci_dev_reset_iommu_done(dev);
+ return ret;
}
bool acpi_pci_power_manageable(struct pci_dev *dev)
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index b14dd064006cc..da0cf0f041516 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -13,6 +13,7 @@
#include <linux/delay.h>
#include <linux/dmi.h>
#include <linux/init.h>
+#include <linux/iommu.h>
#include <linux/msi.h>
#include <linux/of.h>
#include <linux/pci.h>
@@ -25,6 +26,7 @@
#include <linux/logic_pio.h>
#include <linux/device.h>
#include <linux/pm_runtime.h>
+#include <linux/pci-ats.h>
#include <linux/pci_hotplug.h>
#include <linux/vmalloc.h>
#include <asm/dma.h>
@@ -4478,13 +4480,22 @@ EXPORT_SYMBOL(pci_wait_for_pending_transaction);
*/
int pcie_flr(struct pci_dev *dev)
{
+ int ret;
+
if (!pci_wait_for_pending_transaction(dev))
pci_err(dev, "timed out waiting for pending transaction; performing function level reset anyway\n");
+ /* Have to call it after waiting for pending DMA transaction */
+ ret = pci_dev_reset_iommu_prepare(dev);
+ if (ret) {
+ pci_err(dev, "failed to stop IOMMU for a PCI reset: %d\n", ret);
+ return ret;
+ }
+
pcie_capability_set_word(dev, PCI_EXP_DEVCTL, PCI_EXP_DEVCTL_BCR_FLR);
if (dev->imm_ready)
- return 0;
+ goto done;
/*
* Per PCIe r4.0, sec 6.6.2, a device must complete an FLR within
@@ -4493,7 +4504,10 @@ int pcie_flr(struct pci_dev *dev)
*/
msleep(100);
- return pci_dev_wait(dev, "FLR", PCIE_RESET_READY_POLL_MS);
+ ret = pci_dev_wait(dev, "FLR", PCIE_RESET_READY_POLL_MS);
+done:
+ pci_dev_reset_iommu_done(dev);
+ return ret;
}
EXPORT_SYMBOL_GPL(pcie_flr);
@@ -4521,6 +4535,7 @@ EXPORT_SYMBOL_GPL(pcie_reset_flr);
static int pci_af_flr(struct pci_dev *dev, bool probe)
{
+ int ret;
int pos;
u8 cap;
@@ -4547,10 +4562,17 @@ static int pci_af_flr(struct pci_dev *dev, bool probe)
PCI_AF_STATUS_TP << 8))
pci_err(dev, "timed out waiting for pending transaction; performing AF function level reset anyway\n");
+ /* Have to call it after waiting for pending DMA transaction */
+ ret = pci_dev_reset_iommu_prepare(dev);
+ if (ret) {
+ pci_err(dev, "failed to stop IOMMU for a PCI reset: %d\n", ret);
+ return ret;
+ }
+
pci_write_config_byte(dev, pos + PCI_AF_CTRL, PCI_AF_CTRL_FLR);
if (dev->imm_ready)
- return 0;
+ goto done;
/*
* Per Advanced Capabilities for Conventional PCI ECN, 13 April 2006,
@@ -4560,7 +4582,10 @@ static int pci_af_flr(struct pci_dev *dev, bool probe)
*/
msleep(100);
- return pci_dev_wait(dev, "AF_FLR", PCIE_RESET_READY_POLL_MS);
+ ret = pci_dev_wait(dev, "AF_FLR", PCIE_RESET_READY_POLL_MS);
+done:
+ pci_dev_reset_iommu_done(dev);
+ return ret;
}
/**
@@ -4581,6 +4606,7 @@ static int pci_af_flr(struct pci_dev *dev, bool probe)
static int pci_pm_reset(struct pci_dev *dev, bool probe)
{
u16 csr;
+ int ret;
if (!dev->pm_cap || dev->dev_flags & PCI_DEV_FLAGS_NO_PM_RESET)
return -ENOTTY;
@@ -4595,6 +4621,12 @@ static int pci_pm_reset(struct pci_dev *dev, bool probe)
if (dev->current_state != PCI_D0)
return -EINVAL;
+ ret = pci_dev_reset_iommu_prepare(dev);
+ if (ret) {
+ pci_err(dev, "failed to stop IOMMU for a PCI reset: %d\n", ret);
+ return ret;
+ }
+
csr &= ~PCI_PM_CTRL_STATE_MASK;
csr |= PCI_D3hot;
pci_write_config_word(dev, dev->pm_cap + PCI_PM_CTRL, csr);
@@ -4605,7 +4637,9 @@ static int pci_pm_reset(struct pci_dev *dev, bool probe)
pci_write_config_word(dev, dev->pm_cap + PCI_PM_CTRL, csr);
pci_dev_d3_sleep(dev);
- return pci_dev_wait(dev, "PM D3hot->D0", PCIE_RESET_READY_POLL_MS);
+ ret = pci_dev_wait(dev, "PM D3hot->D0", PCIE_RESET_READY_POLL_MS);
+ pci_dev_reset_iommu_done(dev);
+ return ret;
}
/**
@@ -5033,10 +5067,20 @@ static int pci_reset_bus_function(struct pci_dev *dev, bool probe)
return -ENOTTY;
}
+ rc = pci_dev_reset_iommu_prepare(dev);
+ if (rc) {
+ pci_err(dev, "failed to stop IOMMU for a PCI reset: %d\n", rc);
+ return rc;
+ }
+
rc = pci_dev_reset_slot_function(dev, probe);
if (rc != -ENOTTY)
- return rc;
- return pci_parent_bus_reset(dev, probe);
+ goto done;
+
+ rc = pci_parent_bus_reset(dev, probe);
+done:
+ pci_dev_reset_iommu_done(dev);
+ return rc;
}
static int cxl_reset_bus_function(struct pci_dev *dev, bool probe)
@@ -5060,6 +5104,12 @@ static int cxl_reset_bus_function(struct pci_dev *dev, bool probe)
if (rc)
return -ENOTTY;
+ rc = pci_dev_reset_iommu_prepare(dev);
+ if (rc) {
+ pci_err(dev, "failed to stop IOMMU for a PCI reset: %d\n", rc);
+ return rc;
+ }
+
if (reg & PCI_DVSEC_CXL_PORT_CTL_UNMASK_SBR) {
val = reg;
} else {
@@ -5074,6 +5124,7 @@ static int cxl_reset_bus_function(struct pci_dev *dev, bool probe)
pci_write_config_word(bridge, dvsec + PCI_DVSEC_CXL_PORT_CTL,
reg);
+ pci_dev_reset_iommu_done(dev);
return rc;
}
diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
index 214ed060ca1b3..75b6786af01b8 100644
--- a/drivers/pci/quirks.c
+++ b/drivers/pci/quirks.c
@@ -21,6 +21,7 @@
#include <linux/pci.h>
#include <linux/isa-dma.h> /* isa_dma_bridge_buggy */
#include <linux/init.h>
+#include <linux/iommu.h>
#include <linux/delay.h>
#include <linux/acpi.h>
#include <linux/dmi.h>
@@ -4226,6 +4227,22 @@ static const struct pci_dev_reset_methods pci_dev_reset_methods[] = {
{ 0 }
};
+static int __pci_dev_specific_reset(struct pci_dev *dev, bool probe,
+ const struct pci_dev_reset_methods *i)
+{
+ int ret;
+
+ ret = pci_dev_reset_iommu_prepare(dev);
+ if (ret) {
+ pci_err(dev, "failed to stop IOMMU for a PCI reset: %d\n", ret);
+ return ret;
+ }
+
+ ret = i->reset(dev, probe);
+ pci_dev_reset_iommu_done(dev);
+ return ret;
+}
+
/*
* These device-specific reset methods are here rather than in a driver
* because when a host assigns a device to a guest VM, the host may need
@@ -4240,7 +4257,7 @@ int pci_dev_specific_reset(struct pci_dev *dev, bool probe)
i->vendor == (u16)PCI_ANY_ID) &&
(i->device == dev->device ||
i->device == (u16)PCI_ANY_ID))
- return i->reset(dev, probe);
+ return __pci_dev_specific_reset(dev, probe, i);
}
return -ENOTTY;
--
2.43.0
Powered by blists - more mailing lists