Messages in this thread | | | Subject | Re: [PATCH v13 6/6] iommu: Remove mode argument from iommu_set_dma_strict() | From | Robin Murphy <> | Date | Thu, 17 Jun 2021 19:56:44 +0100 |
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On 2021-06-17 08:36, Lu Baolu wrote: > On 6/16/21 7:03 PM, John Garry wrote: >> We only ever now set strict mode enabled in iommu_set_dma_strict(), so >> just remove the argument. >> >> Signed-off-by: John Garry <john.garry@huawei.com> >> Reviewed-by: Robin Murphy <robin.murphy@arm.com> >> --- >> drivers/iommu/amd/init.c | 2 +- >> drivers/iommu/intel/iommu.c | 6 +++--- >> drivers/iommu/iommu.c | 5 ++--- >> include/linux/iommu.h | 2 +- >> 4 files changed, 7 insertions(+), 8 deletions(-) >> >> diff --git a/drivers/iommu/amd/init.c b/drivers/iommu/amd/init.c >> index fb3618af643b..7bc460052678 100644 >> --- a/drivers/iommu/amd/init.c >> +++ b/drivers/iommu/amd/init.c >> @@ -3099,7 +3099,7 @@ static int __init parse_amd_iommu_options(char >> *str) >> for (; *str; ++str) { >> if (strncmp(str, "fullflush", 9) == 0) { >> pr_warn("amd_iommu=fullflush deprecated; use >> iommu.strict instead\n"); >> - iommu_set_dma_strict(true); >> + iommu_set_dma_strict(); >> } >> if (strncmp(str, "force_enable", 12) == 0) >> amd_iommu_force_enable = true; >> diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c >> index d586990fa751..0618c35cfb51 100644 >> --- a/drivers/iommu/intel/iommu.c >> +++ b/drivers/iommu/intel/iommu.c >> @@ -454,7 +454,7 @@ static int __init intel_iommu_setup(char *str) >> iommu_dma_forcedac = true; >> } else if (!strncmp(str, "strict", 6)) { >> pr_warn("intel_iommu=strict deprecated; use iommu.strict >> instead\n"); >> - iommu_set_dma_strict(true); >> + iommu_set_dma_strict(); >> } else if (!strncmp(str, "sp_off", 6)) { >> pr_info("Disable supported super page\n"); >> intel_iommu_superpage = 0; >> @@ -4382,7 +4382,7 @@ int __init intel_iommu_init(void) >> */ >> if (cap_caching_mode(iommu->cap)) { >> pr_warn("IOMMU batching disallowed due to >> virtualization\n"); >> - iommu_set_dma_strict(true); >> + iommu_set_dma_strict(); >> } >> iommu_device_sysfs_add(&iommu->iommu, NULL, >> intel_iommu_groups, >> @@ -5699,7 +5699,7 @@ static void quirk_calpella_no_shadow_gtt(struct >> pci_dev *dev) >> } else if (dmar_map_gfx) { >> /* we have to ensure the gfx device is idle before we flush */ >> pci_info(dev, "Disabling batched IOTLB flush on Ironlake\n"); >> - iommu_set_dma_strict(true); >> + iommu_set_dma_strict(); >> } >> } >> DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x0040, >> quirk_calpella_no_shadow_gtt); >> diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c >> index 60b1ec42e73b..ff221d3ddcbc 100644 >> --- a/drivers/iommu/iommu.c >> +++ b/drivers/iommu/iommu.c >> @@ -349,10 +349,9 @@ static int __init iommu_dma_setup(char *str) >> } >> early_param("iommu.strict", iommu_dma_setup); >> -void iommu_set_dma_strict(bool strict) >> +void iommu_set_dma_strict(void) >> { >> - if (strict || !(iommu_cmd_line & IOMMU_CMD_LINE_STRICT)) >> - iommu_dma_strict = strict; >> + iommu_dma_strict = true; > > Sorry, I still can't get how iommu.strict kernel option works. > > static int __init iommu_dma_setup(char *str) > { > int ret = kstrtobool(str, &iommu_dma_strict);
Note that this is the bit that does the real work - if the argument parses OK then iommu_dma_strict is reassigned with the appropriate value. The iommu_cmd_line stuff is a bit of additional bookkeeping, basically just so we can see whether default values have been overridden.
Robin.
> > if (!ret) > iommu_cmd_line |= IOMMU_CMD_LINE_STRICT; > return ret; > } > early_param("iommu.strict", iommu_dma_setup); > > The bit IOMMU_CMD_LINE_STRICT is only set, but not used anywhere. Hence, > I am wondering how could it work? A bug or I missed anything? > > Best regards, > baolu > >> } >> bool iommu_get_dma_strict(struct iommu_domain *domain) >> diff --git a/include/linux/iommu.h b/include/linux/iommu.h >> index 32d448050bf7..754f67d6dd90 100644 >> --- a/include/linux/iommu.h >> +++ b/include/linux/iommu.h >> @@ -476,7 +476,7 @@ int iommu_enable_nesting(struct iommu_domain >> *domain); >> int iommu_set_pgtable_quirks(struct iommu_domain *domain, >> unsigned long quirks); >> -void iommu_set_dma_strict(bool val); >> +void iommu_set_dma_strict(void); >> bool iommu_get_dma_strict(struct iommu_domain *domain); >> extern int report_iommu_fault(struct iommu_domain *domain, struct >> device *dev, >>
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