linux-kernel - Re: [PATCH 2/2] vfio: hugepage support for vfio_iommu

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Sat, 25 May 2013 07:20:10 -0400
From:	Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
To:	Alex Williamson <alex.williamson@...hat.com>
Cc:	iommu@...ts.linux-foundation.org, chegu_vinod@...com,
	qemu-devel@...gnu.org, kvm@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 2/2] vfio: hugepage support for vfio_iommu_type1

> + * Turns out AMD IOMMU has a page table bug where it won't map large pages
> + * to a region that previously mapped smaller pages.  This should be fixed
> + * soon, so this is just a temporary workaround to break mappings down into
> + * PAGE_SIZE.  Better to map smaller pages than nothing.
> + */
> +static int map_try_harder(struct vfio_iommu *iommu, dma_addr_t iova,
> +			  unsigned long pfn, long npage, int prot)
> +{
> +	long i;
> +	int ret;
> +
> +	for (i = 0; i < npage; i++, pfn++, iova += PAGE_SIZE) {
> +		ret = iommu_map(iommu->domain, iova,
> +				(phys_addr_t)pfn << PAGE_SHIFT,
> +				PAGE_SIZE, prot);
> +		if (ret)
> +			break;
> +	}
> +
> +	for (; i < npage && i > 0; i--, iova -= PAGE_SIZE)
> +		iommu_unmap(iommu->domain, iova, PAGE_SIZE);
> +
>  	return ret;
>  }

This looks to belong to a vfio-quirk file (a something else) that deals with
various IOMMU's quirks.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/