diff options
| -rw-r--r-- | drivers/iommu/intel_irq_remapping.c | 36 |
1 files changed, 28 insertions, 8 deletions
diff --git a/drivers/iommu/intel_irq_remapping.c b/drivers/iommu/intel_irq_remapping.c index 7ca4947c3c10..f3b8f23b5d8f 100644 --- a/drivers/iommu/intel_irq_remapping.c +++ b/drivers/iommu/intel_irq_remapping.c @@ -429,11 +429,22 @@ static void iommu_set_irq_remapping(struct intel_iommu *iommu, int mode) /* Enable interrupt-remapping */ iommu->gcmd |= DMA_GCMD_IRE; + iommu->gcmd &= ~DMA_GCMD_CFI; /* Block compatibility-format MSIs */ writel(iommu->gcmd, iommu->reg + DMAR_GCMD_REG); IOMMU_WAIT_OP(iommu, DMAR_GSTS_REG, readl, (sts & DMA_GSTS_IRES), sts); + /* + * With CFI clear in the Global Command register, we should be + * protected from dangerous (i.e. compatibility) interrupts + * regardless of x2apic status. Check just to be sure. + */ + if (sts & DMA_GSTS_CFIS) + WARN(1, KERN_WARNING + "Compatibility-format IRQs enabled despite intr remapping;\n" + "you are vulnerable to IRQ injection.\n"); + raw_spin_unlock_irqrestore(&iommu->register_lock, flags); } @@ -530,20 +541,24 @@ static int __init intel_irq_remapping_supported(void) static int __init intel_enable_irq_remapping(void) { struct dmar_drhd_unit *drhd; + bool x2apic_present; int setup = 0; int eim = 0; + x2apic_present = x2apic_supported(); + if (parse_ioapics_under_ir() != 1) { printk(KERN_INFO "Not enable interrupt remapping\n"); - return -1; + goto error; } - if (x2apic_supported()) { + if (x2apic_present) { eim = !dmar_x2apic_optout(); - WARN(!eim, KERN_WARNING - "Your BIOS is broken and requested that x2apic be disabled\n" - "This will leave your machine vulnerable to irq-injection attacks\n" - "Use 'intremap=no_x2apic_optout' to override BIOS request\n"); + if (!eim) + printk(KERN_WARNING + "Your BIOS is broken and requested that x2apic be disabled.\n" + "This will slightly decrease performance.\n" + "Use 'intremap=no_x2apic_optout' to override BIOS request.\n"); } for_each_drhd_unit(drhd) { @@ -582,7 +597,7 @@ static int __init intel_enable_irq_remapping(void) if (eim && !ecap_eim_support(iommu->ecap)) { printk(KERN_INFO "DRHD %Lx: EIM not supported by DRHD, " " ecap %Lx\n", drhd->reg_base_addr, iommu->ecap); - return -1; + goto error; } } @@ -598,7 +613,7 @@ static int __init intel_enable_irq_remapping(void) printk(KERN_ERR "DRHD %Lx: failed to enable queued, " " invalidation, ecap %Lx, ret %d\n", drhd->reg_base_addr, iommu->ecap, ret); - return -1; + goto error; } } @@ -637,6 +652,11 @@ error: /* * handle error condition gracefully here! */ + + if (x2apic_present) + WARN(1, KERN_WARNING + "Failed to enable irq remapping. You are vulnerable to irq-injection attacks.\n"); + return -1; } |