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mirror of https://github.com/edk2-porting/linux-next.git synced 2024-12-23 12:43:55 +08:00
linux-next/include
Chenyi Qiang fe6b6bc802 KVM: VMX: Enable bus lock VM exit
Virtual Machine can exploit bus locks to degrade the performance of
system. Bus lock can be caused by split locked access to writeback(WB)
memory or by using locks on uncacheable(UC) memory. The bus lock is
typically >1000 cycles slower than an atomic operation within a cache
line. It also disrupts performance on other cores (which must wait for
the bus lock to be released before their memory operations can
complete).

To address the threat, bus lock VM exit is introduced to notify the VMM
when a bus lock was acquired, allowing it to enforce throttling or other
policy based mitigations.

A VMM can enable VM exit due to bus locks by setting a new "Bus Lock
Detection" VM-execution control(bit 30 of Secondary Processor-based VM
execution controls). If delivery of this VM exit was preempted by a
higher priority VM exit (e.g. EPT misconfiguration, EPT violation, APIC
access VM exit, APIC write VM exit, exception bitmap exiting), bit 26 of
exit reason in vmcs field is set to 1.

In current implementation, the KVM exposes this capability through
KVM_CAP_X86_BUS_LOCK_EXIT. The user can get the supported mode bitmap
(i.e. off and exit) and enable it explicitly (disabled by default). If
bus locks in guest are detected by KVM, exit to user space even when
current exit reason is handled by KVM internally. Set a new field
KVM_RUN_BUS_LOCK in vcpu->run->flags to inform the user space that there
is a bus lock detected in guest.

Document for Bus Lock VM exit is now available at the latest "Intel
Architecture Instruction Set Extensions Programming Reference".

Document Link:
https://software.intel.com/content/www/us/en/develop/download/intel-architecture-instruction-set-extensions-programming-reference.html

Co-developed-by: Xiaoyao Li <xiaoyao.li@intel.com>
Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com>
Signed-off-by: Chenyi Qiang <chenyi.qiang@intel.com>
Message-Id: <20201106090315.18606-4-chenyi.qiang@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-02-04 05:27:21 -05:00
..
acpi More power management updates for 5.11-rc1 2020-12-22 14:12:10 -08:00
asm-generic local64.h: make <asm/local64.h> mandatory 2020-12-29 15:36:49 -08:00
clocksource
crypto crypto: lib/blake2s - Move selftest prototype into header file 2020-12-04 18:13:14 +11:00
drm drm-misc-next for 5.11: 2020-12-15 10:21:48 +01:00
dt-bindings The core framework got some nice improvements this time around. We gained the 2020-12-21 10:39:37 -08:00
keys
kunit
kvm KVM: arm64: Replace KVM_ARM_PMU with HW_PERF_EVENTS 2021-01-04 16:50:16 +00:00
linux KVM/SVM: add support for SEV attestation command 2021-02-04 05:27:20 -05:00
math-emu
media media: rc: add keymap for pine64 remote 2020-12-07 13:51:59 +01:00
memory
misc
net Networking fixes for 5.11-rc3, including fixes from netfilter, wireless 2021-01-05 12:38:56 -08:00
pcmcia
ras
rdma RDMA 5.11 pull request 2020-12-16 13:42:26 -08:00
scsi SCSI misc on 20201216 2020-12-16 13:34:31 -08:00
soc include/soc: remove headers for EZChip NPS 2021-01-05 12:59:41 -08:00
sound ASoC: Updates for v5.11 2020-12-14 15:57:14 +01:00
target
trace Merge branch 'kvm-master' into kvm-next 2021-01-07 18:06:52 -05:00
uapi KVM: VMX: Enable bus lock VM exit 2021-02-04 05:27:21 -05:00
vdso
video
xen xen/xenbus: Count pending messages for each watch 2020-12-14 10:07:13 +01:00