@@ -175,6 +175,16 @@ static void nmi_shootdown_cpus(void)
*/
x2apic_enabled = (current_local_apic_mode() == APIC_MODE_X2APIC);
+ if ( pcidevs_trylock() )
+ {
+ /*
+ * Assume the PCI device list to be in a consistent state if the
+ * lock is not held when the crash happened.
+ */
+ pci_disable_msi_all();
+ pcidevs_unlock();
+ }
+
disable_IO_APIC();
hpet_disable();
}
@@ -86,6 +86,7 @@ extern int pci_enable_msi(struct pci_dev *pdev, struct msi_info *msi,
extern void pci_disable_msi(struct msi_desc *msi_desc);
extern int pci_prepare_msix(u16 seg, u8 bus, u8 devfn, bool off);
extern void pci_cleanup_msi(struct pci_dev *pdev);
+extern void pci_disable_msi_all(void);
extern int setup_msi_irq(struct irq_desc *desc, struct msi_desc *msidesc);
extern int __setup_msi_irq(struct irq_desc *desc, struct msi_desc *msidesc,
hw_irq_controller *handler);
@@ -1248,6 +1248,24 @@ void pci_cleanup_msi(struct pci_dev *pdev)
msi_free_irqs(pdev);
}
+static int cf_check disable_msi(struct pci_dev *pdev, void *arg)
+{
+ msi_set_enable(pdev, 0);
+ msix_set_enable(pdev, 0);
+
+ return 0;
+}
+
+/* Disable MSI and/or MSI-X on all devices known by Xen. */
+void pci_disable_msi_all(void)
+{
+ int rc = pci_iterate_devices(disable_msi, NULL);
+
+ if ( rc )
+ printk(XENLOG_ERR
+ "Failed to disable MSI(-X) on some devices: %d\n", rc);
+}
+
int pci_reset_msix_state(struct pci_dev *pdev)
{
unsigned int pos = pdev->msix_pos;
@@ -374,6 +374,7 @@ void smp_send_stop(void)
smp_call_function(stop_this_cpu, &stop_aps, 0);
local_irq_disable();
+ pci_disable_msi_all();
disable_IO_APIC();
hpet_disable();
@@ -68,6 +68,11 @@ bool pcidevs_locked(void)
return rspin_is_locked(&_pcidevs_lock);
}
+bool pcidevs_trylock_unsafe(void)
+{
+ return _rspin_trylock(&_pcidevs_lock);
+}
+
static RADIX_TREE(pci_segments);
static inline struct pci_seg *get_pseg(u16 seg)
@@ -1802,6 +1807,43 @@ int iommu_do_pci_domctl(
return ret;
}
+struct segment_iter {
+ int (*handler)(struct pci_dev *pdev, void *arg);
+ void *arg;
+ int rc;
+};
+
+static int cf_check iterate_all(struct pci_seg *pseg, void *arg)
+{
+ struct segment_iter *iter = arg;
+ struct pci_dev *pdev;
+
+ list_for_each_entry ( pdev, &pseg->alldevs_list, alldevs_list )
+ {
+ int rc = iter->handler(pdev, iter->arg);
+
+ if ( !iter->rc )
+ iter->rc = rc;
+ }
+
+ return 0;
+}
+
+/*
+ * Iterate without locking or preemption over all PCI devices known by Xen.
+ * Can be called with interrupts disabled.
+ */
+int pci_iterate_devices(int (*handler)(struct pci_dev *pdev, void *arg),
+ void *arg)
+{
+ struct segment_iter iter = {
+ .handler = handler,
+ .arg = arg,
+ };
+
+ return pci_segments_iterate(iterate_all, &iter) ?: iter.rc;
+}
+
/*
* Local variables:
* mode: C
@@ -190,6 +190,11 @@ static always_inline void pcidevs_lock(void)
}
void pcidevs_unlock(void);
bool __must_check pcidevs_locked(void);
+bool pcidevs_trylock_unsafe(void);
+static always_inline bool pcidevs_trylock(void)
+{
+ return lock_evaluate_nospec(pcidevs_trylock_unsafe());
+}
#ifndef NDEBUG
/*
@@ -226,6 +231,13 @@ struct pci_dev *pci_get_pdev(const struct domain *d, pci_sbdf_t sbdf);
struct pci_dev *pci_get_real_pdev(pci_sbdf_t sbdf);
void pci_check_disable_device(u16 seg, u8 bus, u8 devfn);
+/*
+ * Iterate without locking or preemption over all PCI devices known by Xen.
+ * Can be called with interrupts disabled.
+ */
+int pci_iterate_devices(int (*handler)(struct pci_dev *pdev, void *arg),
+ void *arg);
+
uint8_t pci_conf_read8(pci_sbdf_t sbdf, unsigned int reg);
uint16_t pci_conf_read16(pci_sbdf_t sbdf, unsigned int reg);
uint32_t pci_conf_read32(pci_sbdf_t sbdf, unsigned int reg);
Attempt to disable MSI(-X) capabilities on all PCI devices know by Xen at shutdown. Doing such disabling should facilitate kexec chained kernel from booting more reliably, as device MSI(-X) interrupt generation should be quiesced. Only attempt to disable MSI(-X) on all devices in the crash context if the PCI lock is not taken, otherwise the PCI device list could be in an inconsistent state. This requires introducing a new pcidevs_trylock() helper to check whether the lock is currently taken. Disabling MSI(-X) should prevent "Receive accept error" being raised as a result of non-disabled interrupts targeting offline CPUs. Signed-off-by: Roger Pau Monné <roger.pau@citrix.com> --- Changes since v3: - Introduce and use pcidevs_trylock(). - Remove assert from pci_iterate_devices(). Changes since v2: - Disable MSI(-X) ahead of IO-APIC disabling. - Duplicate and expand comment about pci_iterate_devices() in function declaration. - Add assert interrupts are disabled in pci_iterate_devices(). - Only walk PCI device list on crash context if the pci lock is not taken. Changes since v1: - Split from bigger patch. - Iterate over all devices, even if the handler returns failure. --- xen/arch/x86/crash.c | 10 ++++++++ xen/arch/x86/include/asm/msi.h | 1 + xen/arch/x86/msi.c | 18 +++++++++++++++ xen/arch/x86/smp.c | 1 + xen/drivers/passthrough/pci.c | 42 ++++++++++++++++++++++++++++++++++ xen/include/xen/pci.h | 12 ++++++++++ 6 files changed, 84 insertions(+)