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Weinan Liu
9ceebbd6f9
[ Upstream commit69fe699afe] We have observed multiple full invalidations occurring during device detach when we are done using the vfio-device. blocked_domain_attach_device() -> detach_device() -> amd_iommu_domain_flush_all() -> amd_iommu_domain_flush_pages(..., CMD_INV_IOMMU_ALL_PAGES_ADDRESS) while (size != 0) { -> __domain_flush_pages( flush_size /* power of 2 flush_size */) -> domain_flush_pages_v1() -> build_inv_iommu_pages() -> build_inv_address() } build_inv_address() will trigger a full invalidation if the chunk size > (1 << 51). Consequently, the guest will issue multiple full invalidations for a single call to amd_iommu_domain_flush_all() Without this patch, we will see 10 time instead of 1 time full invalidations for every amd_iommu_domain_flush_all(). Cc: stable@vger.kernel.org Fixes:a270be1b3f("iommu/amd: Use only natural aligned flushes in a VM") Suggested-by: Josef Bacik <josef@toxicpanda.com> Suggested-by: Jason Gunthorpe <jgg@nvidia.com> Signed-off-by: Weinan Liu <wnliu@google.com> Reviewed-by: Wei Wang <wei.w.wang@hotmail.com> Reviewed-by: Jason Gunthorpe <jgg@nvidia.com> Reviewed-by: Samiullah Khawaja <skhawaja@google.com> Reviewed-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com> Reviewed-by: Vasant Hegde <vasant.hegde@amd.com> Signed-off-by: Joerg Roedel <joerg.roedel@amd.com> Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.