From: Sean Christopherson <seanjc@google.com>
To: Marc Zyngier <maz@kernel.org>
Cc: Oliver Upton <oupton@google.com>,
kvm@vger.kernel.org, Peter Shier <pshier@google.com>,
kvmarm@lists.cs.columbia.edu
Subject: Re: [PATCH v2 06/11] KVM: arm64: Add support for SYSTEM_SUSPEND PSCI call
Date: Thu, 30 Sep 2021 17:19:18 +0000 [thread overview]
Message-ID: <YVXxlg6g4fYsphwM@google.com> (raw)
In-Reply-To: <877deytfes.wl-maz@kernel.org>
On Thu, Sep 30, 2021, Marc Zyngier wrote:
> Hi Oliver,
>
> On Thu, 23 Sep 2021 20:16:05 +0100,
> Oliver Upton <oupton@google.com> wrote:
> >
> > ARM DEN0022D 5.19 "SYSTEM_SUSPEND" describes a PSCI call that may be
> > used to request a system be suspended. This is optional for PSCI v1.0
> > and to date KVM has elected to not implement the call. However, a
> > VMM/operator may wish to provide their guests with the ability to
> > suspend/resume, necessitating this PSCI call.
> >
> > Implement support for SYSTEM_SUSPEND according to the prescribed
> > behavior in the specification. Add a new system event exit type,
> > KVM_SYSTEM_EVENT_SUSPEND, to notify userspace when a VM has requested a
> > system suspend. Make KVM_MP_STATE_HALTED a valid state on arm64.
>
> KVM_MP_STATE_HALTED is a per-CPU state on x86 (it denotes HLT). Does
> it make really sense to hijack this for something that is more of a
> VM-wide state? I can see that it is tempting to do so as we're using
> the WFI semantics (which are close to HLT's, in a twisted kind of
> way), but I'm also painfully aware that gluing x86 expectations on
> arm64 rarely leads to a palatable result.
Agreed, we literally have billions of possible KVM_MP_STATE_* values, and I'm pretty
sure all of the existing states are arch-specific. Some are common to multiple
architectures, but I don't think _any_ are common to all architectures.
next prev parent reply other threads:[~2021-09-30 17:19 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-23 19:15 [PATCH v2 00/11] KVM: arm64: Implement PSCI SYSTEM_SUSPEND support Oliver Upton
2021-09-23 19:16 ` [PATCH v2 01/11] KVM: arm64: Drop unused vcpu param to kvm_psci_valid_affinity() Oliver Upton
2021-10-01 3:50 ` Reiji Watanabe
2021-10-05 13:22 ` Andrew Jones
2021-09-23 19:16 ` [PATCH v2 02/11] KVM: arm64: Clean up SMC64 PSCI filtering for AArch32 guests Oliver Upton
2021-10-01 3:56 ` Reiji Watanabe
2021-10-05 13:23 ` Andrew Jones
2021-09-23 19:16 ` [PATCH v2 03/11] KVM: arm64: Encapsulate reset request logic in a helper function Oliver Upton
2021-10-01 6:04 ` Reiji Watanabe
2021-10-01 16:10 ` Oliver Upton
2021-10-05 13:33 ` Andrew Jones
2021-10-05 15:05 ` Oliver Upton
2021-10-05 19:01 ` Andrew Jones
2021-10-13 4:48 ` Reiji Watanabe
2021-10-05 13:35 ` Andrew Jones
2021-09-23 19:16 ` [PATCH v2 04/11] KVM: arm64: Rename the KVM_REQ_SLEEP handler Oliver Upton
2021-10-05 13:34 ` Andrew Jones
2021-09-23 19:16 ` [PATCH v2 05/11] KVM: arm64: Defer WFI emulation as a requested event Oliver Upton
2021-09-30 10:50 ` Marc Zyngier
2021-09-30 17:09 ` Sean Christopherson
2021-09-30 17:32 ` Oliver Upton
2021-09-30 18:08 ` Sean Christopherson
2021-09-30 21:57 ` Oliver Upton
2021-10-01 13:57 ` Marc Zyngier
2021-09-23 19:16 ` [PATCH v2 06/11] KVM: arm64: Add support for SYSTEM_SUSPEND PSCI call Oliver Upton
2021-09-30 12:29 ` Marc Zyngier
2021-09-30 17:19 ` Sean Christopherson [this message]
2021-09-30 17:35 ` Oliver Upton
2021-09-30 17:40 ` Oliver Upton
2021-10-01 14:02 ` Marc Zyngier
2021-10-05 16:02 ` Oliver Upton
2021-09-23 19:16 ` [PATCH v2 07/11] selftests: KVM: Rename psci_cpu_on_test to psci_test Oliver Upton
2021-10-05 13:36 ` Andrew Jones
2021-09-23 19:16 ` [PATCH v2 08/11] selftests: KVM: Create helper for making SMCCC calls Oliver Upton
2021-10-05 13:39 ` Andrew Jones
2021-09-23 19:16 ` [PATCH v2 09/11] selftests: KVM: Use KVM_SET_MP_STATE to power off vCPU in psci_test Oliver Upton
2021-09-23 19:16 ` [PATCH v2 10/11] selftests: KVM: Refactor psci_test to make it amenable to new tests Oliver Upton
2021-10-05 13:45 ` Andrew Jones
2021-10-05 14:54 ` Oliver Upton
2021-10-05 19:05 ` Andrew Jones
2021-09-23 19:16 ` [PATCH v2 11/11] selftests: KVM: Test SYSTEM_SUSPEND PSCI call Oliver Upton
2021-10-05 13:49 ` Andrew Jones
2021-10-05 15:07 ` Oliver Upton
2021-09-23 20:15 ` [PATCH v2 00/11] KVM: arm64: Implement PSCI SYSTEM_SUSPEND support Oliver Upton
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