linux-stable.git/include/linux/kvm_types.h, branch v5.16.3

KVM: Kill kvm_map_gfn() / kvm_unmap_gfn() and gfn_to_pfn_cache

2021-11-18T07:03:45+00:00

In commit 7e2175ebd695 ("KVM: x86: Fix recording of guest steal time /
preempted status") I removed the only user of these functions because
it was basically impossible to use them safely.

There are two stages to the GFN->PFN mapping; first through the KVM
memslots to a userspace HVA and then through the page tables to
translate that HVA to an underlying PFN. Invalidations of the former
were being handled correctly, but no attempt was made to use the MMU
notifiers to invalidate the cache when the HVA->GFN mapping changed.

As a prelude to reinventing the gfn_to_pfn_cache with more usable
semantics, rip it out entirely and untangle the implementation of
the unsafe kvm_vcpu_map()/kvm_vcpu_unmap() functions from it.

All current users of kvm_vcpu_map() also look broken right now, and
will be dealt with separately. They broadly fall into two classes:

* Those which map, access the data and immediately unmap. This is
  mostly gratuitous and could just as well use the existing user
  HVA, and could probably benefit from a gfn_to_hva_cache as they
  do so.

* Those which keep the mapping around for a longer time, perhaps
  even using the PFN directly from the guest. These will need to
  be converted to the new gfn_to_pfn_cache and then kvm_vcpu_map()
  can be removed too.

Signed-off-by: David Woodhouse 
Message-Id: <20211115165030.7422-8-dwmw2@infradead.org>
Signed-off-by: Paolo Bonzini

KVM: stats: Add VM stat for remote tlb flush requests

2021-09-06T10:30:45+00:00

Add a new stat that counts the number of times a remote TLB flush is
requested, regardless of whether it kicks vCPUs out of guest mode. This
allows us to look at how often flushes are initiated.

Unlike remote_tlb_flush, this one applies to ARM's instruction-set-based
TLB flush implementation, so apply it there too.

Original-by: David Matlack 
Signed-off-by: Jing Zhang 
Message-Id: <20210817002639.3856694-1-jingzhangos@google.com>
Signed-off-by: Paolo Bonzini

KVM: stats: Add halt polling related histogram stats

2021-08-20T20:06:33+00:00

Add three log histogram stats to record the distribution of time spent
on successful polling, failed polling and VCPU wait.
halt_poll_success_hist: Distribution of spent time for a successful poll.
halt_poll_fail_hist: Distribution of spent time for a failed poll.
halt_wait_hist: Distribution of time a VCPU has spent on waiting.

Signed-off-by: Jing Zhang 
Message-Id: <20210802165633.1866976-6-jingzhangos@google.com>
Signed-off-by: Paolo Bonzini

KVM: stats: Add halt_wait_ns stats for all architectures

2021-08-20T20:06:33+00:00

Add simple stats halt_wait_ns to record the time a VCPU has spent on
waiting for all architectures (not just powerpc).

Signed-off-by: Jing Zhang 
Message-Id: <20210802165633.1866976-5-jingzhangos@google.com>
Signed-off-by: Paolo Bonzini

KVM: stats: Add fd-based API to read binary stats data

2021-06-24T15:47:57+00:00

This commit defines the API for userspace and prepare the common
functionalities to support per VM/VCPU binary stats data readings.

The KVM stats now is only accessible by debugfs, which has some
shortcomings this change series are supposed to fix:
1. The current debugfs stats solution in KVM could be disabled
   when kernel Lockdown mode is enabled, which is a potential
   rick for production.
2. The current debugfs stats solution in KVM is organized as "one
   stats per file", it is good for debugging, but not efficient
   for production.
3. The stats read/clear in current debugfs solution in KVM are
   protected by the global kvm_lock.

Besides that, there are some other benefits with this change:
1. All KVM VM/VCPU stats can be read out in a bulk by one copy
   to userspace.
2. A schema is used to describe KVM statistics. From userspace's
   perspective, the KVM statistics are self-describing.
3. With the fd-based solution, a separate telemetry would be able
   to read KVM stats in a less privileged environment.
4. After the initial setup by reading in stats descriptors, a
   telemetry only needs to read the stats data itself, no more
   parsing or setup is needed.

Reviewed-by: David Matlack 
Reviewed-by: Ricardo Koller 
Reviewed-by: Krish Sadhukhan 
Reviewed-by: Fuad Tabba 
Tested-by: Fuad Tabba  #arm64
Signed-off-by: Jing Zhang 
Message-Id: <20210618222709.1858088-3-jingzhangos@google.com>
Signed-off-by: Paolo Bonzini

KVM: stats: Separate generic stats from architecture specific ones

2021-06-24T15:47:56+00:00

Generic KVM stats are those collected in architecture independent code
or those supported by all architectures; put all generic statistics in
a separate structure.  This ensures that they are defined the same way
in the statistics API which is being added, removing duplication among
different architectures in the declaration of the descriptors.

No functional change intended.

Reviewed-by: David Matlack 
Reviewed-by: Ricardo Koller 
Reviewed-by: Krish Sadhukhan 
Signed-off-by: Jing Zhang 
Message-Id: <20210618222709.1858088-2-jingzhangos@google.com>
Signed-off-by: Paolo Bonzini

KVM: Move x86's version of struct kvm_mmu_memory_cache to common code

2020-07-09T17:29:42+00:00

Move x86's 'struct kvm_mmu_memory_cache' to common code in anticipation
of moving the entire x86 implementation code to common KVM and reusing
it for arm64 and MIPS.  Add a new architecture specific asm/kvm_types.h
to control the existence and parameters of the struct.  The new header
is needed to avoid a chicken-and-egg problem with asm/kvm_host.h as all
architectures define instances of the struct in their vCPU structs.

Add an asm-generic version of kvm_types.h to avoid having empty files on
PPC and s390 in the long term, and for arm64 and mips in the short term.

Suggested-by: Christoffer Dall 
Reviewed-by: Ben Gardon 
Signed-off-by: Sean Christopherson 
Message-Id: <20200703023545.8771-15-sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini

x86/kvm: Cache gfn to pfn translation

2020-01-30T17:45:55+00:00

__kvm_map_gfn()'s call to gfn_to_pfn_memslot() is
* relatively expensive
* in certain cases (such as when done from atomic context) cannot be called

Stashing gfn-to-pfn mapping should help with both cases.

This is part of CVE-2019-3016.

Signed-off-by: Boris Ostrovsky 
Reviewed-by: Joao Martins 
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini

KVM: arm64: Support stolen time reporting via shared structure

2019-10-21T18:20:28+00:00

Implement the service call for configuring a shared structure between a
VCPU and the hypervisor in which the hypervisor can write the time
stolen from the VCPU's execution time by other tasks on the host.

User space allocates memory which is placed at an IPA also chosen by user
space. The hypervisor then updates the shared structure using
kvm_put_guest() to ensure single copy atomicity of the 64-bit value
reporting the stolen time in nanoseconds.

Whenever stolen time is enabled by the guest, the stolen time counter is
reset.

The stolen time itself is retrieved from the sched_info structure
maintained by the Linux scheduler code. We enable SCHEDSTATS when
selecting KVM Kconfig to ensure this value is meaningful.

Signed-off-by: Steven Price 
Signed-off-by: Marc Zyngier

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 503

2019-06-19T15:09:56+00:00

Based on 1 normalized pattern(s):

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license as published by
  the free software foundation either version 2 of the license this
  program is distributed in the hope that it will be useful but
  without any warranty without even the implied warranty of
  merchantability or fitness for a particular purpose see the gnu
  general public license for more details you should have received a
  copy of the gnu general public license along with this program if
  not write to the free software foundation 51 franklin street fifth
  floor boston ma 02110 1301 usa

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-only

has been chosen to replace the boilerplate/reference in 1 file(s).

Signed-off-by: Thomas Gleixner 
Reviewed-by: Kate Stewart 
Reviewed-by: Allison Randal 
Reviewed-by: Enrico Weigelt 
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190604081207.308909165@linutronix.de
Signed-off-by: Greg Kroah-Hartman