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authorLinus Torvalds <torvalds@linux-foundation.org>2023-06-27 11:33:47 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2023-06-27 11:33:47 -0700
commita3540495324af9b7fa95b62da2ccbf7cdb4e3622 (patch)
tree82062f3a1a9894c165f18f63a81ad561af32244a /Documentation/virt
parentdedbf31ac8a57eaa29b6e4f9745dadffa83dd947 (diff)
parenta1e72bb00a48687a1dc1c2e549eaf4ba09e802be (diff)
downloadlinux-a3540495324af9b7fa95b62da2ccbf7cdb4e3622.tar.gz
Merge tag 'docs-6.5' of git://git.lwn.net/linux
Pull documentation updates from Jonathan Corbet: "It's been a relatively calm cycle in docsland. We do have: - Some initial page-table documentation from Linus (the other Linus) - Regression-handling documentation improvements from Thorsten - Addition of kerneldoc documentation for the ERR_PTR() and related macros from James Seo ... and the usual collection of fixes and updates" * tag 'docs-6.5' of git://git.lwn.net/linux: docs: consolidate storage interfaces Documentation: update git configuration for Link: tag Documentation: KVM: make corrections to vcpu-requests.rst Documentation: KVM: make corrections to ppc-pv.rst Documentation: KVM: make corrections to locking.rst Documentation: KVM: make corrections to halt-polling.rst Documentation: virt: correct location of haltpoll module params Documentation/mm: Initial page table documentation docs: crypto: async-tx-api: fix typo in struct name docs/doc-guide: Clarify how to write tables docs: handling-regressions: rework section about fixing procedures docs: process: fix a typoed cross-reference docs: submitting-patches: Discuss interleaved replies MAINTAINERS: direct process doc changes to a dedicated ML Documentation: core-api: Add error pointer functions to kernel-api err.h: Add missing kerneldocs for error pointer functions Documentation: conf.py: Add __force to c_id_attributes docs: clarify KVM related kernel parameters' descriptions docs: consolidate human interface subsystems docs: admin-guide: Add information about intel_pstate active mode
Diffstat (limited to 'Documentation/virt')
-rw-r--r--Documentation/virt/guest-halt-polling.rst2
-rw-r--r--Documentation/virt/kvm/halt-polling.rst10
-rw-r--r--Documentation/virt/kvm/locking.rst18
-rw-r--r--Documentation/virt/kvm/ppc-pv.rst8
-rw-r--r--Documentation/virt/kvm/vcpu-requests.rst6
5 files changed, 22 insertions, 22 deletions
diff --git a/Documentation/virt/guest-halt-polling.rst b/Documentation/virt/guest-halt-polling.rst
index b4e747942417ad..922291ddc40c6e 100644
--- a/Documentation/virt/guest-halt-polling.rst
+++ b/Documentation/virt/guest-halt-polling.rst
@@ -72,7 +72,7 @@ high once achieves global guest_halt_poll_ns value).
Default: Y
-The module parameters can be set from the debugfs files in::
+The module parameters can be set from the sysfs files in::
/sys/module/haltpoll/parameters/
diff --git a/Documentation/virt/kvm/halt-polling.rst b/Documentation/virt/kvm/halt-polling.rst
index 3fae39b1a5ba31..4f1a1b23d99cb0 100644
--- a/Documentation/virt/kvm/halt-polling.rst
+++ b/Documentation/virt/kvm/halt-polling.rst
@@ -112,11 +112,11 @@ powerpc kvm-hv case.
| | function. | |
+-----------------------+---------------------------+-------------------------+
-These module parameters can be set from the debugfs files in:
+These module parameters can be set from the sysfs files in:
/sys/module/kvm/parameters/
-Note: that these module parameters are system wide values and are not able to
+Note: these module parameters are system-wide values and are not able to
be tuned on a per vm basis.
Any changes to these parameters will be picked up by new and existing vCPUs the
@@ -142,12 +142,12 @@ Further Notes
global max polling interval (halt_poll_ns) then the host will always poll for the
entire block time and thus cpu utilisation will go to 100%.
-- Halt polling essentially presents a trade off between power usage and latency and
+- Halt polling essentially presents a trade-off between power usage and latency and
the module parameters should be used to tune the affinity for this. Idle cpu time is
essentially converted to host kernel time with the aim of decreasing latency when
entering the guest.
- Halt polling will only be conducted by the host when no other tasks are runnable on
that cpu, otherwise the polling will cease immediately and schedule will be invoked to
- allow that other task to run. Thus this doesn't allow a guest to denial of service the
- cpu.
+ allow that other task to run. Thus this doesn't allow a guest to cause denial of service
+ of the cpu.
diff --git a/Documentation/virt/kvm/locking.rst b/Documentation/virt/kvm/locking.rst
index 8c77554e489634..3a034db5e55f89 100644
--- a/Documentation/virt/kvm/locking.rst
+++ b/Documentation/virt/kvm/locking.rst
@@ -67,7 +67,7 @@ following two cases:
2. Write-Protection: The SPTE is present and the fault is caused by
write-protect. That means we just need to change the W bit of the spte.
-What we use to avoid all the race is the Host-writable bit and MMU-writable bit
+What we use to avoid all the races is the Host-writable bit and MMU-writable bit
on the spte:
- Host-writable means the gfn is writable in the host kernel page tables and in
@@ -130,7 +130,7 @@ to gfn. For indirect sp, we disabled fast page fault for simplicity.
A solution for indirect sp could be to pin the gfn, for example via
kvm_vcpu_gfn_to_pfn_atomic, before the cmpxchg. After the pinning:
-- We have held the refcount of pfn that means the pfn can not be freed and
+- We have held the refcount of pfn; that means the pfn can not be freed and
be reused for another gfn.
- The pfn is writable and therefore it cannot be shared between different gfns
by KSM.
@@ -186,22 +186,22 @@ writable between reading spte and updating spte. Like below case:
The Dirty bit is lost in this case.
In order to avoid this kind of issue, we always treat the spte as "volatile"
-if it can be updated out of mmu-lock, see spte_has_volatile_bits(), it means,
+if it can be updated out of mmu-lock [see spte_has_volatile_bits()]; it means
the spte is always atomically updated in this case.
3) flush tlbs due to spte updated
-If the spte is updated from writable to readonly, we should flush all TLBs,
+If the spte is updated from writable to read-only, we should flush all TLBs,
otherwise rmap_write_protect will find a read-only spte, even though the
writable spte might be cached on a CPU's TLB.
As mentioned before, the spte can be updated to writable out of mmu-lock on
-fast page fault path, in order to easily audit the path, we see if TLBs need
-be flushed caused by this reason in mmu_spte_update() since this is a common
+fast page fault path. In order to easily audit the path, we see if TLBs needing
+to be flushed caused this reason in mmu_spte_update() since this is a common
function to update spte (present -> present).
Since the spte is "volatile" if it can be updated out of mmu-lock, we always
-atomically update the spte, the race caused by fast page fault can be avoided,
+atomically update the spte and the race caused by fast page fault can be avoided.
See the comments in spte_has_volatile_bits() and mmu_spte_update().
Lockless Access Tracking:
@@ -283,9 +283,9 @@ time it will be set using the Dirty tracking mechanism described above.
:Arch: x86
:Protects: wakeup_vcpus_on_cpu
:Comment: This is a per-CPU lock and it is used for VT-d posted-interrupts.
- When VT-d posted-interrupts is supported and the VM has assigned
+ When VT-d posted-interrupts are supported and the VM has assigned
devices, we put the blocked vCPU on the list blocked_vcpu_on_cpu
- protected by blocked_vcpu_on_cpu_lock, when VT-d hardware issues
+ protected by blocked_vcpu_on_cpu_lock. When VT-d hardware issues
wakeup notification event since external interrupts from the
assigned devices happens, we will find the vCPU on the list to
wakeup.
diff --git a/Documentation/virt/kvm/ppc-pv.rst b/Documentation/virt/kvm/ppc-pv.rst
index 5fdb907670be01..740d03d2530032 100644
--- a/Documentation/virt/kvm/ppc-pv.rst
+++ b/Documentation/virt/kvm/ppc-pv.rst
@@ -89,7 +89,7 @@ also define a new hypercall feature to indicate that the host can give you more
registers. Only if the host supports the additional features, make use of them.
The magic page layout is described by struct kvm_vcpu_arch_shared
-in arch/powerpc/include/asm/kvm_para.h.
+in arch/powerpc/include/uapi/asm/kvm_para.h.
Magic page features
===================
@@ -112,7 +112,7 @@ Magic page flags
================
In addition to features that indicate whether a host is capable of a particular
-feature we also have a channel for a guest to tell the guest whether it's capable
+feature we also have a channel for a guest to tell the host whether it's capable
of something. This is what we call "flags".
Flags are passed to the host in the low 12 bits of the Effective Address.
@@ -139,7 +139,7 @@ Patched instructions
====================
The "ld" and "std" instructions are transformed to "lwz" and "stw" instructions
-respectively on 32 bit systems with an added offset of 4 to accommodate for big
+respectively on 32-bit systems with an added offset of 4 to accommodate for big
endianness.
The following is a list of mapping the Linux kernel performs when running as
@@ -210,7 +210,7 @@ available on all targets.
2) PAPR hypercalls
PAPR hypercalls are needed to run server PowerPC PAPR guests (-M pseries in QEMU).
-These are the same hypercalls that pHyp, the POWER hypervisor implements. Some of
+These are the same hypercalls that pHyp, the POWER hypervisor, implements. Some of
them are handled in the kernel, some are handled in user space. This is only
available on book3s_64.
diff --git a/Documentation/virt/kvm/vcpu-requests.rst b/Documentation/virt/kvm/vcpu-requests.rst
index 87f04c1fa53d1c..06718b9bc95977 100644
--- a/Documentation/virt/kvm/vcpu-requests.rst
+++ b/Documentation/virt/kvm/vcpu-requests.rst
@@ -101,7 +101,7 @@ also be used, e.g. ::
However, VCPU request users should refrain from doing so, as it would
break the abstraction. The first 8 bits are reserved for architecture
-independent requests, all additional bits are available for architecture
+independent requests; all additional bits are available for architecture
dependent requests.
Architecture Independent Requests
@@ -151,8 +151,8 @@ KVM_REQUEST_NO_WAKEUP
This flag is applied to requests that only need immediate attention
from VCPUs running in guest mode. That is, sleeping VCPUs do not need
- to be awaken for these requests. Sleeping VCPUs will handle the
- requests when they are awaken later for some other reason.
+ to be awakened for these requests. Sleeping VCPUs will handle the
+ requests when they are awakened later for some other reason.
KVM_REQUEST_WAIT