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Message-ID: <20120521131532.GL2313@8bytes.org>
Date: Mon, 21 May 2012 15:15:32 +0200
From: Joerg Roedel <joro@...tes.org>
To: Bjorn Helgaas <bhelgaas@...gle.com>
Cc: David Woodhouse <dwmw2@...radead.org>,
linux-kernel@...r.kernel.org, iommu@...ts.linux-foundation.org,
Ingo Molnar <mingo@...e.hu>,
Suresh Siddha <suresh.b.siddha@...el.com>
Subject: Re: [PATCH 2/2] iommu: Request IOMMU CSR space
On Fri, May 18, 2012 at 05:18:37PM -0600, Bjorn Helgaas wrote:
> 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 <bhelgaas@...gle.com>
Looks good.
Reviewed-by: Joerg Roedel <joro@...tes.org>
> ---
> 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 */
>
> --
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