Yet another reason why trusting this stuff to the BIOS was a bad idea.
There now seem to be a bunch of BIOSes which report an IOMMU at a
physical address which just returns all ones. (Perhaps only when VT-d is
actually _disabled_ in the BIOS?)
Well done, Dell and HP -- although I didn't think it was possible, you
have _further_ lowered my already-unprintable opinion of closed source
BIOSes and BIOS engineers.
This patch makes the kernel detect this particularly brokenness and
abort early -- and fixes up the missing iounmap in the error paths which
I noticed while I was poking at it.
This should fix kernel.org bug #14003, which was being called a
'regression' -- I think because the IOMMU code used to trip over
_another_ BIOS bug earlier than this one, and that one _did_ cause it to
abort.
Signed-off-by: David Woodhouse <David.Woodhouse@xxxxxxxxx>
---
drivers/pci/dmar.c | 22 ++++++++++++++++++----
1 files changed, 18 insertions(+), 4 deletions(-)
diff --git a/drivers/pci/dmar.c b/drivers/pci/dmar.c
index 7b287cb..380b60e 100644
--- a/drivers/pci/dmar.c
+++ b/drivers/pci/dmar.c
@@ -632,20 +632,31 @@ int alloc_iommu(struct dmar_drhd_unit *drhd)
iommu->cap = dmar_readq(iommu->reg + DMAR_CAP_REG);
iommu->ecap = dmar_readq(iommu->reg + DMAR_ECAP_REG);
+ if (iommu->cap == (uint64_t)-1 && iommu->ecap == (uint64_t)-1) {
+ /* Promote an attitude of violence to a BIOS engineer today */
+ WARN(1, "Your BIOS is broken; DMAR reported at address %llx returns all ones!\n"
+ "BIOS vendor: %s; Ver: %s; Product Version: %s\n",
+ drhd->reg_base_addr,
+ dmi_get_system_info(DMI_BIOS_VENDOR),
+ dmi_get_system_info(DMI_BIOS_VERSION),
+ dmi_get_system_info(DMI_PRODUCT_VERSION));
+ goto err_unmap;
+ }
+
#ifdef CONFIG_DMAR
agaw = iommu_calculate_agaw(iommu);
if (agaw < 0) {
printk(KERN_ERR
"Cannot get a valid agaw for iommu (seq_id = %d)\n",
iommu->seq_id);
- goto error;
+ goto err_unmap;
}
msagaw = iommu_calculate_max_sagaw(iommu);
if (msagaw < 0) {
printk(KERN_ERR
"Cannot get a valid max agaw for iommu (seq_id = %d)\n",
iommu->seq_id);
- goto error;
+ goto err_unmap;
}
#endif
iommu->agaw = agaw;
@@ -665,7 +676,7 @@ int alloc_iommu(struct dmar_drhd_unit *drhd)
}
ver = readl(iommu->reg + DMAR_VER_REG);
- pr_debug("IOMMU %llx: ver %d:%d cap %llx ecap %llx\n",
+ pr_info("IOMMU %llx: ver %d:%d cap %llx ecap %llx\n",
(unsigned long long)drhd->reg_base_addr,
DMAR_VER_MAJOR(ver), DMAR_VER_MINOR(ver),
(unsigned long long)iommu->cap,
@@ -675,7 +686,10 @@ int alloc_iommu(struct dmar_drhd_unit *drhd)
drhd->iommu = iommu;
return 0;
-error:
+
+ err_unmap:
+ iounmap(iommu->reg);
+ error:
kfree(iommu);
return -1;
}
--
1.6.2.5
--
dwmw2
--
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