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Filename Latest commit message Latest commit date
Sean Christopherson 0ebcfdc8c9 KVM: nVMX: Properly expose ENABLE_USR_WAIT_PAUSE control to L1
[ Upstream commit 31de69f4eea77b28a9724b3fa55aae104fc91fc7 ]

Set ENABLE_USR_WAIT_PAUSE in KVM's supported VMX MSR configuration if the
feature is supported in hardware and enabled in KVM's base, non-nested
configuration, i.e. expose ENABLE_USR_WAIT_PAUSE to L1 if it's supported.
This fixes a bug where saving/restoring, i.e. migrating, a vCPU will fail
if WAITPKG (the associated CPUID feature) is enabled for the vCPU, and
obviously allows L1 to enable the feature for L2.

KVM already effectively exposes ENABLE_USR_WAIT_PAUSE to L1 by stuffing
the allowed-1 control ina vCPU's virtual MSR_IA32_VMX_PROCBASED_CTLS2 when
updating secondary controls in response to KVM_SET_CPUID(2), but (a) that
depends on flawed code (KVM shouldn't touch VMX MSRs in response to CPUID
updates) and (b) runs afoul of vmx_restore_control_msr()'s restriction
that the guest value must be a strict subset of the supported host value.

Although no past commit explicitly enabled nested support for WAITPKG,
doing so is safe and functionally correct from an architectural
perspective as no additional KVM support is needed to virtualize TPAUSE,
UMONITOR, and UMWAIT for L2 relative to L1, and KVM already forwards
VM-Exits to L1 as necessary (commit bf653b78f9, "KVM: vmx: Introduce
handle_unexpected_vmexit and handle WAITPKG vmexit").

Note, KVM always keeps the hosts MSR_IA32_UMWAIT_CONTROL resident in
hardware, i.e. always runs both L1 and L2 with the host's power management
settings for TPAUSE and UMWAIT.  See commit bf09fb6cba4f ("KVM: VMX: Stop
context switching MSR_IA32_UMWAIT_CONTROL") for more details.

Fixes: e69e72faa3 ("KVM: x86: Add support for user wait instructions")
Cc: stable@vger.kernel.org
Reported-by: Aaron Lewis <aaronlewis@google.com>
Reported-by: Yu Zhang <yu.c.zhang@linux.intel.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
Message-Id: <20221213062306.667649-2-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-01-18 11:41:54 +01:00
arch KVM: nVMX: Properly expose ENABLE_USR_WAIT_PAUSE control to L1 2023-01-18 11:41:54 +01:00
block blk-mq: fix possible memleak when register 'hctx' failed 2023-01-18 11:41:38 +01:00
certs
crypto crypto: tcrypt - Fix multibuffer skcipher speed test mem leak 2023-01-18 11:41:19 +01:00
Documentation ASoC: dt-bindings: wcd9335: fix reset line polarity in example 2023-01-18 11:41:06 +01:00
drivers dm thin: resume even if in FAIL mode 2023-01-18 11:41:53 +01:00
fs btrfs: replace strncpy() with strscpy() 2023-01-18 11:41:52 +01:00
include PM/devfreq: governor: Add a private governor_data for governor 2023-01-18 11:41:52 +01:00
init init/Kconfig: fix CC_HAS_ASM_GOTO_TIED_OUTPUT test with dash 2022-12-08 11:22:59 +01:00
ipc ipc/sem: Fix dangling sem_array access in semtimedop race 2022-12-08 11:23:06 +01:00
kernel tracing: Fix infinite loop in tracing_read_pipe on overflowed print_trace_line 2023-01-18 11:41:48 +01:00
lib test_firmware: fix memory leak in test_firmware_init() 2023-01-18 11:41:23 +01:00
LICENSES
mm mm, compaction: fix fast_isolate_around() to stay within boundaries 2023-01-18 11:41:44 +01:00
net net/af_packet: make sure to pull mac header 2023-01-18 11:41:45 +01:00
samples samples: vfio-mdev: Fix missing pci_disable_device() in mdpy_fb_probe() 2023-01-18 11:41:26 +01:00
scripts scripts/faddr2line: Fix regression in name resolution on ppc64le 2022-12-08 11:23:02 +01:00
security device_cgroup: Roll back to original exceptions after copy failure 2023-01-18 11:41:50 +01:00
sound ALSA: line6: fix stack overflow in line6_midi_transmit 2023-01-18 11:41:44 +01:00
tools KVM: VMX: Fix the spelling of CPU_BASED_USE_TSC_OFFSETTING 2023-01-18 11:41:54 +01:00
usr
virt KVM: arm64: vgic: Fix exit condition in scan_its_table() 2022-10-29 10:20:35 +02:00
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Makefile Linux 5.4.228 2022-12-19 12:24:17 +01:00
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.