Request the IOMMU CSR MMIO region to keep anybody else from claiming it while we're using it.
The bug referenced below is a crash that happened when we assigned an address in the IOMMU CSR area to a PCI BAR. This patch just changes the IOMMU driver, which only helps when the driver is present, so a BIOS change is also necessary. But the driver should claim the space it uses in any event. Reference: https://bugzilla.novell.com/show_bug.cgi?id=760440 Signed-off-by: Bjorn Helgaas <bhelg...@google.com> --- drivers/iommu/dmar.c | 41 ++++++++++++++++++++++++++++++++--------- include/linux/intel-iommu.h | 2 ++ 2 files changed, 34 insertions(+), 9 deletions(-) diff --git a/drivers/iommu/dmar.c b/drivers/iommu/dmar.c index 35c1e17..e4ac23a 100644 --- a/drivers/iommu/dmar.c +++ b/drivers/iommu/dmar.c @@ -581,6 +581,7 @@ int __init detect_intel_iommu(void) int alloc_iommu(struct dmar_drhd_unit *drhd) { struct intel_iommu *iommu; + struct resource *res; int map_size; u32 ver; static int iommu_allocated = 0; @@ -599,11 +600,20 @@ int alloc_iommu(struct dmar_drhd_unit *drhd) iommu->seq_id = iommu_allocated++; sprintf (iommu->name, "dmar%d", iommu->seq_id); - iommu->reg = ioremap(drhd->reg_base_addr, VTD_PAGE_SIZE); - if (!iommu->reg) { - printk(KERN_ERR "IOMMU: can't map the region\n"); + iommu->reg_base = drhd->reg_base_addr; + iommu->reg_size = VTD_PAGE_SIZE; + res = request_mem_region(iommu->reg_base, iommu->reg_size, iommu->name); + if (!res) { + printk(KERN_ERR "IOMMU: can't request [mem %#010llx-%#010llx]\n", + iommu->reg_base, iommu->reg_base + iommu->reg_size - 1); goto error; } + + iommu->reg = ioremap(iommu->reg_base, iommu->reg_size); + if (!iommu->reg) { + printk(KERN_ERR "IOMMU: can't map %pR\n", res); + goto err_release; + } iommu->cap = dmar_readq(iommu->reg + DMAR_CAP_REG); iommu->ecap = dmar_readq(iommu->reg + DMAR_ECAP_REG); @@ -637,17 +647,26 @@ int alloc_iommu(struct dmar_drhd_unit *drhd) map_size = VTD_PAGE_ALIGN(map_size); if (map_size > VTD_PAGE_SIZE) { iounmap(iommu->reg); - iommu->reg = ioremap(drhd->reg_base_addr, map_size); + release_mem_region(iommu->reg_base, iommu->reg_size); + iommu->reg_size = map_size; + res = request_mem_region(iommu->reg_base, iommu->reg_size, + iommu->name); + if (!res) { + printk(KERN_ERR "IOMMU: can't request [mem %#010llx-%#010llx]\n", + iommu->reg_base, + iommu->reg_base + iommu->reg_size - 1); + goto error; + } + iommu->reg = ioremap(iommu->reg_base, iommu->reg_size); if (!iommu->reg) { - printk(KERN_ERR "IOMMU: can't map the region\n"); + printk(KERN_ERR "IOMMU: can't map %pR\n", res); goto error; } } ver = readl(iommu->reg + DMAR_VER_REG); - pr_info("IOMMU %d: reg_base_addr %llx ver %d:%d cap %llx ecap %llx\n", - iommu->seq_id, - (unsigned long long)drhd->reg_base_addr, + pr_info("IOMMU %d: %pR ver %d:%d cap %llx ecap %llx\n", + iommu->seq_id, res, DMAR_VER_MAJOR(ver), DMAR_VER_MINOR(ver), (unsigned long long)iommu->cap, (unsigned long long)iommu->ecap); @@ -659,6 +678,8 @@ int alloc_iommu(struct dmar_drhd_unit *drhd) err_unmap: iounmap(iommu->reg); + err_release: + release_mem_region(iommu->reg_base, iommu->reg_size); error: kfree(iommu); return -1; @@ -671,8 +692,10 @@ void free_iommu(struct intel_iommu *iommu) free_dmar_iommu(iommu); - if (iommu->reg) + if (iommu->reg) { iounmap(iommu->reg); + release_mem_region(iommu->reg_base, iommu->reg_size); + } kfree(iommu); } diff --git a/include/linux/intel-iommu.h b/include/linux/intel-iommu.h index e6ca56d..911ded0 100644 --- a/include/linux/intel-iommu.h +++ b/include/linux/intel-iommu.h @@ -308,6 +308,8 @@ enum { struct intel_iommu { void __iomem *reg; /* Pointer to hardware regs, virtual addr */ + phys_addr_t reg_base; + resource_size_t reg_size; u64 cap; u64 ecap; u32 gcmd; /* Holds TE, EAFL. Don't need SRTP, SFL, WBF */ _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu
