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From: Hikaru Nishida <hikalium@chromium.org>
To: kvm@vger.kernel.org
Cc: suleiman@google.com, Hikaru Nishida <hikalium@chromium.org>,
	Borislav Petkov <bp@alien8.de>, "H. Peter Anvin" <hpa@zytor.com>,
	Ingo Molnar <mingo@redhat.com>, Jim Mattson <jmattson@google.com>,
	Joerg Roedel <joro@8bytes.org>,
	John Stultz <john.stultz@linaro.org>,
	Jonathan Corbet <corbet@lwn.net>,
	Paolo Bonzini <pbonzini@redhat.com>,
	Sean Christopherson <seanjc@google.com>,
	Stephen Boyd <sboyd@kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Vitaly Kuznetsov <vkuznets@redhat.com>,
	Wanpeng Li <wanpengli@tencent.com>,
	linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
	x86@kernel.org
Subject: [RFC PATCH 0/6] x86/kvm: Virtual suspend time injection support
Date: Mon, 26 Apr 2021 18:06:39 +0900	[thread overview]
Message-ID: <20210426090644.2218834-1-hikalium@chromium.org> (raw)


Hi,

This patch series adds virtual suspend time injection support to KVM.

Before this change, if the host goes into suspended state while the
guest is running, the guest will experience a time jump after the host's
resume. This can confuse some services in the guest since they can't
detect if the system went into suspend or not by comparing
CLOCK_BOOTTIME and CLOCK_MONOTONIC.

To solve this problem, we wanted to add a way to adjust the guest clocks
without actually suspending the guests. However, there was no way to
modify a gap between CLOCK_BOOTTIME and CLOCK_MONOTONIC without actually
suspending the guests. Therefore, this series introduce a new struct
called kvm_host_suspend_time to share the suspend time between host and
guest and a mechanism to inject a suspend time to the guest while
keeping
monotonicity of the clocks.

Could you take a look and let me know how we can improve the patches if
they are doing something wrong?

Thanks,

Hikaru Nishida



Hikaru Nishida (6):
  x86/kvm: Reserve KVM_FEATURE_HOST_SUSPEND_TIME and
    MSR_KVM_HOST_SUSPEND_TIME
  x86/kvm: Add a struct and constants for virtual suspend time injection
  x86/kvm: Add CONFIG_KVM_VIRT_SUSPEND_TIMING
  x86/kvm: Add a host side support for virtual suspend time injection
  x86/kvm: Add CONFIG_KVM_VIRT_SUSPEND_TIMING_GUEST
  x86/kvm: Add a guest side support for virtual suspend time injection

 Documentation/virt/kvm/cpuid.rst     |  3 +
 Documentation/virt/kvm/msr.rst       | 29 +++++++++
 arch/x86/Kconfig                     | 13 ++++
 arch/x86/include/asm/kvm_host.h      |  5 ++
 arch/x86/include/asm/kvm_para.h      |  9 +++
 arch/x86/include/uapi/asm/kvm_para.h |  6 ++
 arch/x86/kernel/kvmclock.c           | 25 ++++++++
 arch/x86/kvm/Kconfig                 | 13 ++++
 arch/x86/kvm/cpuid.c                 |  4 ++
 arch/x86/kvm/x86.c                   | 89 +++++++++++++++++++++++++++-
 include/linux/kvm_host.h             |  7 +++
 include/linux/timekeeper_internal.h  |  4 ++
 kernel/time/timekeeping.c            | 31 ++++++++++
 13 files changed, 237 insertions(+), 1 deletion(-)

-- 
2.31.1.498.g6c1eba8ee3d-goog


             reply	other threads:[~2021-04-26  9:09 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-26  9:06 Hikaru Nishida [this message]
2021-04-26  9:06 ` [RFC PATCH 1/6] x86/kvm: Reserve KVM_FEATURE_HOST_SUSPEND_TIME and MSR_KVM_HOST_SUSPEND_TIME Hikaru Nishida
2021-04-27 15:12   ` David Edmondson
2021-04-26  9:06 ` [RFC PATCH 2/6] x86/kvm: Add a struct and constants for virtual suspend time injection Hikaru Nishida
2021-04-27 15:14   ` David Edmondson
2021-04-26  9:06 ` [RFC PATCH 3/6] x86/kvm: Add CONFIG_KVM_VIRT_SUSPEND_TIMING Hikaru Nishida
2021-04-26  9:06 ` [RFC PATCH 4/6] x86/kvm: Add a host side support for virtual suspend time injection Hikaru Nishida
2021-04-27 15:20   ` David Edmondson
2021-04-26  9:06 ` [RFC PATCH 5/6] x86/kvm: Add CONFIG_KVM_VIRT_SUSPEND_TIMING_GUEST Hikaru Nishida
2021-04-26  9:06 ` [RFC PATCH 6/6] x86/kvm: Add a guest side support for virtual suspend time injection Hikaru Nishida
2021-04-26 14:21   ` Thomas Gleixner
2021-04-26 13:15 ` [RFC PATCH 0/6] x86/kvm: Virtual suspend time injection support Maxim Levitsky

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