92dcb50f7f
commit a2bad844a67b1c7740bda63e87453baf63c3a7f7 upstream. According to Dexuan, the hypervisor folks beleive that multi-msi allocations are not correct. compose_msi_msg() will allocate multi-msi one by one. However, multi-msi is a block of related MSIs, with alignment requirements. In order for the hypervisor to allocate properly aligned and consecutive entries in the IOMMU Interrupt Remapping Table, there should be a single mapping request that requests all of the multi-msi vectors in one shot. Dexuan suggests detecting the multi-msi case and composing a single request related to the first MSI. Then for the other MSIs in the same block, use the cached information. This appears to be viable, so do it. 5.15 backport - add hv_msi_get_int_vector helper function. Fixed merge conflict due to delivery_mode name change (APIC_DELIVERY_MODE_FIXED is the value given to DELIVERY_MODE on x86). Removed unused variable in hv_compose_msi_msg. Fixed reference to msi_desc->pci to point to the same is_msix variable. Suggested-by: Dexuan Cui <decui@microsoft.com> Signed-off-by: Jeffrey Hugo <quic_jhugo@quicinc.com> Reviewed-by: Dexuan Cui <decui@microsoft.com> Tested-by: Michael Kelley <mikelley@microsoft.com> Link: https://lore.kernel.org/r/1652282599-21643-1-git-send-email-quic_jhugo@quicinc.com Signed-off-by: Wei Liu <wei.liu@kernel.org> Signed-off-by: Carl Vanderlip <quic_carlv@quicinc.com> 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.