From: Paolo Bonzini <pbonzini@redhat.com>
To: Vitaly Kuznetsov <vkuznets@redhat.com>, kvm@vger.kernel.org
Cc: Sean Christopherson <seanjc@google.com>,
Wanpeng Li <wanpengli@tencent.com>,
Jim Mattson <jmattson@google.com>,
Maxim Levitsky <mlevitsk@redhat.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3 0/4] KVM: x86: hyper-v: Conditionally allow SynIC with APICv/AVIC
Date: Thu, 10 Jun 2021 15:17:49 +0200 [thread overview]
Message-ID: <dea0b7f2-20ff-36c4-d020-18bff8bc58e0@redhat.com> (raw)
In-Reply-To: <20210609150911.1471882-1-vkuznets@redhat.com>
On 09/06/21 17:09, Vitaly Kuznetsov wrote:
> Changes since v2:
> - First two patches got merged, rebase.
> - Use 'enable_apicv = avic = ...' in PATCH1 [Paolo]
> - Collect R-b tags for PATCH2 [Sean, Max]
> - Use hv_apicv_update_work() to get out of SRCU lock [Max]
> - "KVM: x86: Check for pending interrupts when APICv is getting disabled"
> added.
>
> Original description:
>
> APICV_INHIBIT_REASON_HYPERV is currently unconditionally forced upon
> SynIC activation as SynIC's AutoEOI is incompatible with APICv/AVIC. It is,
> however, possible to track whether the feature was actually used by the
> guest and only inhibit APICv/AVIC when needed.
>
> The series can be tested with the followin hack:
>
> diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
> index 9a48f138832d..65a9974f80d9 100644
> --- a/arch/x86/kvm/cpuid.c
> +++ b/arch/x86/kvm/cpuid.c
> @@ -147,6 +147,13 @@ void kvm_update_cpuid_runtime(struct kvm_vcpu *vcpu)
> vcpu->arch.ia32_misc_enable_msr &
> MSR_IA32_MISC_ENABLE_MWAIT);
> }
> +
> + /* Dirty hack: force HV_DEPRECATING_AEOI_RECOMMENDED. Not to be merged! */
> + best = kvm_find_cpuid_entry(vcpu, HYPERV_CPUID_ENLIGHTMENT_INFO, 0);
> + if (best) {
> + best->eax &= ~HV_X64_APIC_ACCESS_RECOMMENDED;
> + best->eax |= HV_DEPRECATING_AEOI_RECOMMENDED;
> + }
> }
> EXPORT_SYMBOL_GPL(kvm_update_cpuid_runtime);
>
> Vitaly Kuznetsov (4):
> KVM: x86: Use common 'enable_apicv' variable for both APICv and AVIC
> KVM: x86: Drop vendor specific functions for APICv/AVIC enablement
> KVM: x86: Check for pending interrupts when APICv is getting disabled
> KVM: x86: hyper-v: Deactivate APICv only when AutoEOI feature is in
> use
>
> arch/x86/include/asm/kvm_host.h | 9 +++++-
> arch/x86/kvm/hyperv.c | 51 +++++++++++++++++++++++++++++----
> arch/x86/kvm/svm/avic.c | 14 ++++-----
> arch/x86/kvm/svm/svm.c | 22 ++++++++------
> arch/x86/kvm/svm/svm.h | 2 --
> arch/x86/kvm/vmx/capabilities.h | 1 -
> arch/x86/kvm/vmx/vmx.c | 2 --
> arch/x86/kvm/x86.c | 18 ++++++++++--
> 8 files changed, 86 insertions(+), 33 deletions(-)
>
Queued, thanks.
Paolo
next prev parent reply other threads:[~2021-06-10 13:17 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-09 15:09 [PATCH v3 0/4] KVM: x86: hyper-v: Conditionally allow SynIC with APICv/AVIC Vitaly Kuznetsov
2021-06-09 15:09 ` [PATCH v3 1/4] KVM: x86: Use common 'enable_apicv' variable for both APICv and AVIC Vitaly Kuznetsov
2021-06-09 15:09 ` [PATCH v3 2/4] KVM: x86: Drop vendor specific functions for APICv/AVIC enablement Vitaly Kuznetsov
2021-06-09 15:09 ` [PATCH v3 3/4] KVM: x86: Check for pending interrupts when APICv is getting disabled Vitaly Kuznetsov
2021-06-09 15:09 ` [PATCH v3 4/4] KVM: x86: hyper-v: Deactivate APICv only when AutoEOI feature is in use Vitaly Kuznetsov
2021-06-10 13:17 ` Paolo Bonzini [this message]
2021-06-11 18:50 ` [PATCH v3 0/4] KVM: x86: hyper-v: Conditionally allow SynIC with APICv/AVIC Maxim Levitsky
2021-06-14 7:40 ` Vitaly Kuznetsov
2021-06-14 9:51 ` Maxim Levitsky
2021-06-14 13:08 ` Paolo Bonzini
2021-06-14 18:21 ` Maxim Levitsky
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