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Filename Latest commit message Latest commit date
Jeffrey Hugo 8e94cc8830 PCI: hv: Fix multi-MSI to allow more than one MSI vector
commit 08e61e861a0e47e5e1a3fb78406afd6b0cea6b6d upstream.

If the allocation of multiple MSI vectors for multi-MSI fails in the core
PCI framework, the framework will retry the allocation as a single MSI
vector, assuming that meets the min_vecs specified by the requesting
driver.

Hyper-V advertises that multi-MSI is supported, but reuses the VECTOR
domain to implement that for x86.  The VECTOR domain does not support
multi-MSI, so the alloc will always fail and fallback to a single MSI
allocation.

In short, Hyper-V advertises a capability it does not implement.

Hyper-V can support multi-MSI because it coordinates with the hypervisor
to map the MSIs in the IOMMU's interrupt remapper, which is something the
VECTOR domain does not have.  Therefore the fix is simple - copy what the
x86 IOMMU drivers (AMD/Intel-IR) do by removing
X86_IRQ_ALLOC_CONTIGUOUS_VECTORS after calling the VECTOR domain's
pci_msi_prepare().

5.4 backport - adds the hv_msi_prepare wrapper function.
X86_IRQ_ALLOC_TYPE_PCI_MSI changed to X86_IRQ_ALLOC_TYPE_MSI
(same value).

Fixes: 4daace0d8c ("PCI: hv: Add paravirtual PCI front-end for Microsoft Hyper-V VMs")
Signed-off-by: Jeffrey Hugo <quic_jhugo@quicinc.com>
Reviewed-by: Dexuan Cui <decui@microsoft.com>
Link: https://lore.kernel.org/r/1649856981-14649-1-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>
2022-07-29 17:14:09 +02:00
arch riscv: add as-options for modules with assembly compontents 2022-07-29 17:14:08 +02:00
block
certs certs/blacklist_hashes.c: fix const confusion in certs blacklist 2022-06-22 14:11:22 +02:00
crypto crypto: drbg - make reseeding from get_random_bytes() synchronous 2022-06-22 14:11:18 +02:00
Documentation ipv4: Fix data-races around sysctl_ip_dynaddr. 2022-07-21 20:59:22 +02:00
drivers PCI: hv: Fix multi-MSI to allow more than one MSI vector 2022-07-29 17:14:09 +02:00
fs ext4: fix race condition between ext4_write and ext4_convert_inline_data 2022-07-21 20:59:18 +02:00
include raw: Fix a data-race around sysctl_raw_l3mdev_accept. 2022-07-21 20:59:22 +02:00
init random: handle latent entropy and command line from random_init() 2022-06-22 14:11:17 +02:00
ipc
kernel signal handling: don't use BUG_ON() for debugging 2022-07-21 20:59:27 +02:00
lib ida: don't use BUG_ON() for debugging 2022-07-12 16:30:49 +02:00
LICENSES
mm mm/slub: add missing TID updates on slab deactivation 2022-07-12 16:30:46 +02:00
net net: tipc: fix possible refcount leak in tipc_sk_create() 2022-07-21 20:59:25 +02:00
samples
scripts modpost: fix section mismatch check for exported init/exit sections 2022-06-29 08:58:49 +02:00
security lockdown: Fix kexec lockdown bypass with ima policy 2022-07-29 17:14:09 +02:00
sound ASoC: madera: Fix event generation for rate controls 2022-07-21 20:59:26 +02:00
tools selftests: forwarding: fix error message in learning_test 2022-07-12 16:30:49 +02:00
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Makefile Linux 5.4.207 2022-07-21 20:59:29 +02:00
README

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.