From: Hikaru Nishida <hikalium@chromium.org>
To: linux-kernel@vger.kernel.org, dme@dme.org, tglx@linutronix.de,
mlevitsk@redhat.com
Cc: suleiman@google.com, Hikaru Nishida <hikalium@chromium.org>,
Jonathan Corbet <corbet@lwn.net>,
Paolo Bonzini <pbonzini@redhat.com>,
kvm@vger.kernel.org, linux-doc@vger.kernel.org
Subject: [v2 PATCH 1/4] x86/kvm: Reserve KVM_FEATURE_HOST_SUSPEND_TIME and MSR_KVM_HOST_SUSPEND_TIME
Date: Fri, 6 Aug 2021 19:07:07 +0900 [thread overview]
Message-ID: <20210806190607.v2.1.I2a67009253163b8eecf1ae8d050c541d35ac0bd8@changeid> (raw)
In-Reply-To: <20210806100710.2425336-1-hikalium@chromium.org>
No functional change; just add documentation for
KVM_FEATURE_HOST_SUSPEND_TIME and its corresponding
MSR_KVM_HOST_SUSPEND_TIME to support virtual suspend timing injection in
later patches.
Signed-off-by: Hikaru Nishida <hikalium@chromium.org>
---
Documentation/virt/kvm/cpuid.rst | 3 +++
Documentation/virt/kvm/msr.rst | 30 ++++++++++++++++++++++++++++++
2 files changed, 33 insertions(+)
diff --git a/Documentation/virt/kvm/cpuid.rst b/Documentation/virt/kvm/cpuid.rst
index bda3e3e737d7..f17b95b0d943 100644
--- a/Documentation/virt/kvm/cpuid.rst
+++ b/Documentation/virt/kvm/cpuid.rst
@@ -103,6 +103,9 @@ KVM_FEATURE_HC_MAP_GPA_RANGE 16 guest checks this feature bit bef
KVM_FEATURE_MIGRATION_CONTROL 17 guest checks this feature bit before
using MSR_KVM_MIGRATION_CONTROL
+KVM_FEATURE_HOST_SUSPEND_TIME 18 host suspend time information
+ is available at msr 0x4b564d09.
+
KVM_FEATURE_CLOCKSOURCE_STABLE_BIT 24 host will warn if no guest-side
per-cpu warps are expected in
kvmclock
diff --git a/Documentation/virt/kvm/msr.rst b/Documentation/virt/kvm/msr.rst
index 9315fc385fb0..a218a350d0d0 100644
--- a/Documentation/virt/kvm/msr.rst
+++ b/Documentation/virt/kvm/msr.rst
@@ -389,3 +389,33 @@ data:
guest is communicating page encryption status to the host using the
``KVM_HC_MAP_GPA_RANGE`` hypercall, it can set bit 0 in this MSR to
allow live migration of the guest.
+
+MSR_KVM_HOST_SUSPEND_TIME:
+ 0x4b564d09
+
+data:
+ 8-byte alignment physical address of a memory area which must be
+ in guest RAM, plus an enable bit in bit 0. This memory is expected to
+ hold a copy of the following structure::
+
+ struct kvm_suspend_time {
+ __u64 suspend_time_ns;
+ };
+
+ whose data will be filled in by the hypervisor.
+ If the guest register this structure through the MSR write, the host
+ will stop all the clocks including TSCs observed by the guest during
+ the host's suspension and report the duration of suspend through this
+ structure. The update will be notified through
+ VIRT_SUSPEND_TIMING_VECTOR IRQ. Fields have the following meanings:
+
+ suspend_time_ns:
+ Total number of nanoseconds passed during the host's suspend
+ while the VM is running. This value will be increasing
+ monotonically.
+
+ Note that although MSRs are per-CPU entities, the effect of this
+ particular MSR is global.
+
+ Availability of this MSR must be checked via bit 18 in 0x4000001 cpuid
+ leaf prior to usage.
--
2.32.0.605.g8dce9f2422-goog
next prev parent reply other threads:[~2021-08-06 10:07 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-06 10:07 [v2 PATCH 0/4] x86/kvm: Virtual suspend time injection support Hikaru Nishida
2021-08-06 10:07 ` Hikaru Nishida [this message]
2021-08-06 10:07 ` [v2 PATCH 2/4] x86/kvm: Add definitions for virtual suspend time injection Hikaru Nishida
2021-08-10 15:14 ` Thomas Gleixner
2021-08-13 18:36 ` Guenter Roeck
2021-08-06 10:07 ` [v2 PATCH 3/4] x86/kvm: Add host side support " Hikaru Nishida
2021-08-10 15:21 ` Thomas Gleixner
2021-08-10 15:24 ` Thomas Gleixner
2021-08-14 7:22 ` Paolo Bonzini
2021-08-18 9:32 ` Vitaly Kuznetsov
2021-08-18 20:49 ` Paolo Bonzini
2021-08-06 10:07 ` [v2 PATCH 4/4] x86/kvm: Add guest " Hikaru Nishida
2021-08-10 15:48 ` Thomas Gleixner
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20210806190607.v2.1.I2a67009253163b8eecf1ae8d050c541d35ac0bd8@changeid \
--to=hikalium@chromium.org \
--cc=corbet@lwn.net \
--cc=dme@dme.org \
--cc=kvm@vger.kernel.org \
--cc=linux-doc@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mlevitsk@redhat.com \
--cc=pbonzini@redhat.com \
--cc=suleiman@google.com \
--cc=tglx@linutronix.de \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).