| Message ID | 1483536746-2725-14-git-send-email-eric.auger@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Hi Eric, On 04/01/17 13:32, Eric Auger wrote: > This new function checks whether all platform and PCI > MSI domains implement IRQ remapping. This is useful to > understand whether VFIO passthrough is safe with respect > to interrupts. > > On ARM typically an MSI controller can sit downstream > to the IOMMU without preventing VFIO passthrough. > As such any assigned device can write into the MSI doorbell. > In case the MSI controller implements IRQ remapping, assigned > devices will not be able to trigger interrupts towards the > host. On the contrary, the assignment must be emphasized as > unsafe with respect to interrupts. > > Signed-off-by: Eric Auger <eric.auger@redhat.com> > > --- > > v4 -> v5: > - Handle DOMAIN_BUS_FSL_MC_MSI domains > - Check parents > --- > include/linux/irqdomain.h | 1 + > kernel/irq/irqdomain.c | 41 +++++++++++++++++++++++++++++++++++++++++ > 2 files changed, 42 insertions(+) > > diff --git a/include/linux/irqdomain.h b/include/linux/irqdomain.h > index ab017b2..281a40f 100644 > --- a/include/linux/irqdomain.h > +++ b/include/linux/irqdomain.h > @@ -219,6 +219,7 @@ struct irq_domain *irq_domain_add_legacy(struct device_node *of_node, > void *host_data); > extern struct irq_domain *irq_find_matching_fwspec(struct irq_fwspec *fwspec, > enum irq_domain_bus_token bus_token); > +extern bool irq_domain_check_msi_remap(void); > extern void irq_set_default_host(struct irq_domain *host); > extern int irq_domain_alloc_descs(int virq, unsigned int nr_irqs, > irq_hw_number_t hwirq, int node, > diff --git a/kernel/irq/irqdomain.c b/kernel/irq/irqdomain.c > index 8c0a0ae..700caea 100644 > --- a/kernel/irq/irqdomain.c > +++ b/kernel/irq/irqdomain.c > @@ -278,6 +278,47 @@ struct irq_domain *irq_find_matching_fwspec(struct irq_fwspec *fwspec, > EXPORT_SYMBOL_GPL(irq_find_matching_fwspec); > > /** > + * irq_domain_is_msi_remap - Check if @domain or any parent > + * has MSI remapping support > + * @domain: domain pointer > + */ > +static bool irq_domain_is_msi_remap(struct irq_domain *domain) > +{ > + struct irq_domain *h = domain; > + > + for (; h; h = h->parent) { > + if (h->flags & IRQ_DOMAIN_FLAG_MSI_REMAP) > + return true; > + } > + return false; > +} > + > +/** > + * irq_domain_check_msi_remap() - Checks whether all MSI > + * irq domains implement IRQ remapping > + */ > +bool irq_domain_check_msi_remap(void) > +{ > + struct irq_domain *h; > + bool ret = true; > + > + mutex_lock(&irq_domain_mutex); > + list_for_each_entry(h, &irq_domain_list, link) { > + if (((h->bus_token & DOMAIN_BUS_PCI_MSI) || > + (h->bus_token & DOMAIN_BUS_PLATFORM_MSI) || > + (h->bus_token & DOMAIN_BUS_FSL_MC_MSI)) && > + !irq_domain_is_msi_remap(h)) { (h->bus_token & DOMAIN_BUS_PCI_MSI) and co looks quite wrong. bus_token is not a bitmap, and DOMAIN_BUS_* not a single bit value (see enum irq_domain_bus_token). Surely this should read (h->bus_token == DOMAIN_BUS_PCI_MSI). Thanks, M.
Hi Marc, On 04/01/2017 14:46, Marc Zyngier wrote: > Hi Eric, > > On 04/01/17 13:32, Eric Auger wrote: >> This new function checks whether all platform and PCI >> MSI domains implement IRQ remapping. This is useful to >> understand whether VFIO passthrough is safe with respect >> to interrupts. >> >> On ARM typically an MSI controller can sit downstream >> to the IOMMU without preventing VFIO passthrough. >> As such any assigned device can write into the MSI doorbell. >> In case the MSI controller implements IRQ remapping, assigned >> devices will not be able to trigger interrupts towards the >> host. On the contrary, the assignment must be emphasized as >> unsafe with respect to interrupts. >> >> Signed-off-by: Eric Auger <eric.auger@redhat.com> >> >> --- >> >> v4 -> v5: >> - Handle DOMAIN_BUS_FSL_MC_MSI domains >> - Check parents >> --- >> include/linux/irqdomain.h | 1 + >> kernel/irq/irqdomain.c | 41 +++++++++++++++++++++++++++++++++++++++++ >> 2 files changed, 42 insertions(+) >> >> diff --git a/include/linux/irqdomain.h b/include/linux/irqdomain.h >> index ab017b2..281a40f 100644 >> --- a/include/linux/irqdomain.h >> +++ b/include/linux/irqdomain.h >> @@ -219,6 +219,7 @@ struct irq_domain *irq_domain_add_legacy(struct device_node *of_node, >> void *host_data); >> extern struct irq_domain *irq_find_matching_fwspec(struct irq_fwspec *fwspec, >> enum irq_domain_bus_token bus_token); >> +extern bool irq_domain_check_msi_remap(void); >> extern void irq_set_default_host(struct irq_domain *host); >> extern int irq_domain_alloc_descs(int virq, unsigned int nr_irqs, >> irq_hw_number_t hwirq, int node, >> diff --git a/kernel/irq/irqdomain.c b/kernel/irq/irqdomain.c >> index 8c0a0ae..700caea 100644 >> --- a/kernel/irq/irqdomain.c >> +++ b/kernel/irq/irqdomain.c >> @@ -278,6 +278,47 @@ struct irq_domain *irq_find_matching_fwspec(struct irq_fwspec *fwspec, >> EXPORT_SYMBOL_GPL(irq_find_matching_fwspec); >> >> /** >> + * irq_domain_is_msi_remap - Check if @domain or any parent >> + * has MSI remapping support >> + * @domain: domain pointer >> + */ >> +static bool irq_domain_is_msi_remap(struct irq_domain *domain) >> +{ >> + struct irq_domain *h = domain; >> + >> + for (; h; h = h->parent) { >> + if (h->flags & IRQ_DOMAIN_FLAG_MSI_REMAP) >> + return true; >> + } >> + return false; >> +} >> + >> +/** >> + * irq_domain_check_msi_remap() - Checks whether all MSI >> + * irq domains implement IRQ remapping >> + */ >> +bool irq_domain_check_msi_remap(void) >> +{ >> + struct irq_domain *h; >> + bool ret = true; >> + >> + mutex_lock(&irq_domain_mutex); >> + list_for_each_entry(h, &irq_domain_list, link) { >> + if (((h->bus_token & DOMAIN_BUS_PCI_MSI) || >> + (h->bus_token & DOMAIN_BUS_PLATFORM_MSI) || >> + (h->bus_token & DOMAIN_BUS_FSL_MC_MSI)) && >> + !irq_domain_is_msi_remap(h)) { > > (h->bus_token & DOMAIN_BUS_PCI_MSI) and co looks quite wrong. bus_token > is not a bitmap, and DOMAIN_BUS_* not a single bit value (see enum > irq_domain_bus_token). Surely this should read > (h->bus_token == DOMAIN_BUS_PCI_MSI). Oh I did not notice that. Thanks. Any other comments on the irqdomain side? Do you think the current approach consisting in looking at those bus tokens and their parents looks good? Thanks Eric > > Thanks, > > M. > -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Hi Eric,
[auto build test ERROR on linus/master]
[also build test ERROR on v4.10-rc2 next-20170105]
[cannot apply to iommu/next]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]
url: https://github.com/0day-ci/linux/commits/Eric-Auger/KVM-PCIe-MSI-passthrough-on-ARM-ARM64-and-IOVA-reserved-regions/20170105-132853
config: i386-randconfig-x003-201701 (attached as .config)
compiler: gcc-6 (Debian 6.2.0-3) 6.2.0 20160901
reproduce:
# save the attached .config to linux build tree
make ARCH=i386
All errors (new ones prefixed by >>):
kernel/irq/irqdomain.c: In function 'irq_domain_is_msi_remap':
>> kernel/irq/irqdomain.c:289:17: error: 'struct irq_domain' has no member named 'parent'
for (; h; h = h->parent) {
^~
vim +289 kernel/irq/irqdomain.c
283 * @domain: domain pointer
284 */
285 static bool irq_domain_is_msi_remap(struct irq_domain *domain)
286 {
287 struct irq_domain *h = domain;
288
> 289 for (; h; h = h->parent) {
290 if (h->flags & IRQ_DOMAIN_FLAG_MSI_REMAP)
291 return true;
292 }
---
0-DAY kernel test infrastructure Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all Intel Corporation
diff --git a/include/linux/irqdomain.h b/include/linux/irqdomain.h index ab017b2..281a40f 100644 --- a/include/linux/irqdomain.h +++ b/include/linux/irqdomain.h @@ -219,6 +219,7 @@ struct irq_domain *irq_domain_add_legacy(struct device_node *of_node, void *host_data); extern struct irq_domain *irq_find_matching_fwspec(struct irq_fwspec *fwspec, enum irq_domain_bus_token bus_token); +extern bool irq_domain_check_msi_remap(void); extern void irq_set_default_host(struct irq_domain *host); extern int irq_domain_alloc_descs(int virq, unsigned int nr_irqs, irq_hw_number_t hwirq, int node, diff --git a/kernel/irq/irqdomain.c b/kernel/irq/irqdomain.c index 8c0a0ae..700caea 100644 --- a/kernel/irq/irqdomain.c +++ b/kernel/irq/irqdomain.c @@ -278,6 +278,47 @@ struct irq_domain *irq_find_matching_fwspec(struct irq_fwspec *fwspec, EXPORT_SYMBOL_GPL(irq_find_matching_fwspec); /** + * irq_domain_is_msi_remap - Check if @domain or any parent + * has MSI remapping support + * @domain: domain pointer + */ +static bool irq_domain_is_msi_remap(struct irq_domain *domain) +{ + struct irq_domain *h = domain; + + for (; h; h = h->parent) { + if (h->flags & IRQ_DOMAIN_FLAG_MSI_REMAP) + return true; + } + return false; +} + +/** + * irq_domain_check_msi_remap() - Checks whether all MSI + * irq domains implement IRQ remapping + */ +bool irq_domain_check_msi_remap(void) +{ + struct irq_domain *h; + bool ret = true; + + mutex_lock(&irq_domain_mutex); + list_for_each_entry(h, &irq_domain_list, link) { + if (((h->bus_token & DOMAIN_BUS_PCI_MSI) || + (h->bus_token & DOMAIN_BUS_PLATFORM_MSI) || + (h->bus_token & DOMAIN_BUS_FSL_MC_MSI)) && + !irq_domain_is_msi_remap(h)) { + ret = false; + goto out; + } + } +out: + mutex_unlock(&irq_domain_mutex); + return ret; +} +EXPORT_SYMBOL_GPL(irq_domain_check_msi_remap); + +/** * irq_set_default_host() - Set a "default" irq domain * @domain: default domain pointer *
This new function checks whether all platform and PCI MSI domains implement IRQ remapping. This is useful to understand whether VFIO passthrough is safe with respect to interrupts. On ARM typically an MSI controller can sit downstream to the IOMMU without preventing VFIO passthrough. As such any assigned device can write into the MSI doorbell. In case the MSI controller implements IRQ remapping, assigned devices will not be able to trigger interrupts towards the host. On the contrary, the assignment must be emphasized as unsafe with respect to interrupts. Signed-off-by: Eric Auger <eric.auger@redhat.com> --- v4 -> v5: - Handle DOMAIN_BUS_FSL_MC_MSI domains - Check parents --- include/linux/irqdomain.h | 1 + kernel/irq/irqdomain.c | 41 +++++++++++++++++++++++++++++++++++++++++ 2 files changed, 42 insertions(+)