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From: Paolo Bonzini <pbonzini@redhat.com>
To: David Woodhouse <dwmw2@infradead.org>, kvm@vger.kernel.org
Cc: Ankur Arora <ankur.a.arora@oracle.com>,
	Joao Martins <joao.m.martins@oracle.com>,
	Boris Ostrovsky <boris.ostrovsky@oracle.com>,
	Sean Christopherson <seanjc@google.com>,
	graf@amazon.com, iaslan@amazon.de, pdurrant@amazon.com,
	aagch@amazon.com, fandree@amazon.com, hch@infradead.org
Subject: Re: [PATCH v5 16/16] KVM: x86/xen: Add event channel interrupt vector upcall
Date: Fri, 29 Jan 2021 20:19:55 +0100	[thread overview]
Message-ID: <97fef86f-fef3-3ee8-9ae9-2144d19fc2a5@redhat.com> (raw)
In-Reply-To: <529a1e82a0c83f82e0079359b0b8ba74ac670e89.camel@infradead.org>

On 29/01/21 18:33, David Woodhouse wrote:
> On Thu, 2021-01-28 at 13:43 +0100, Paolo Bonzini wrote:
>> Independent of the answer to the above, this is really the only place
>> where you're adding Xen code to a hot path.  Can you please use a
>> STATIC_KEY_FALSE kvm_has_xen_vcpu (and a static inline function) to
>> quickly return from kvm_xen_has_interrupt() if no vCPU has a shared info
>> set up?
> 
> Something like this, then?
> 
>  From 6504c78f76efd8c60630959111bd77c28d43fca7 Mon Sep 17 00:00:00 2001
> From: David Woodhouse <dwmw@amazon.co.uk>
> Date: Fri, 29 Jan 2021 17:30:40 +0000
> Subject: [PATCH] KVM: x86/xen: Add static branch to avoid overhead of checking
>   Xen upcall vector
> 
> Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>

Yes, that was the idea.  Thanks!

Paolo


  reply	other threads:[~2021-01-29 19:24 UTC|newest]

Thread overview: 35+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-11 19:57 [PATCH v5 00/16] KVM: Add minimal support for Xen HVM guests David Woodhouse
2021-01-11 19:57 ` [PATCH v5 01/16] KVM: x86/xen: fix Xen hypercall page msr handling David Woodhouse
2021-01-11 19:57 ` [PATCH v5 02/16] KVM: x86/xen: intercept xen hypercalls if enabled David Woodhouse
2021-01-11 23:42   ` kernel test robot
2021-01-11 23:42     ` kernel test robot
2021-01-28 12:21   ` Paolo Bonzini
2021-01-11 19:57 ` [PATCH v5 03/16] KVM: x86/xen: Fix coexistence of Xen and Hyper-V hypercalls David Woodhouse
2021-01-11 19:57 ` [PATCH v5 04/16] KVM: x86/xen: add KVM_XEN_HVM_SET_ATTR/KVM_XEN_HVM_GET_ATTR David Woodhouse
2021-01-11 19:57 ` [PATCH v5 05/16] KVM: x86/xen: latch long_mode when hypercall page is set up David Woodhouse
2021-01-11 19:57 ` [PATCH v5 06/16] KVM: x86/xen: add definitions of compat_shared_info, compat_vcpu_info David Woodhouse
2021-01-11 19:57 ` [PATCH v5 07/16] KVM: x86/xen: register shared_info page David Woodhouse
2021-01-11 19:57 ` [PATCH v5 08/16] xen: add wc_sec_hi to struct shared_info David Woodhouse
2021-01-11 19:57 ` [PATCH v5 09/16] KVM: x86/xen: update wallclock region David Woodhouse
2021-01-11 19:57 ` [PATCH v5 10/16] KVM: x86/xen: register vcpu info David Woodhouse
2021-01-11 19:57 ` [PATCH v5 11/16] KVM: x86/xen: setup pvclock updates David Woodhouse
2021-01-11 19:57 ` [PATCH v5 12/16] KVM: x86/xen: register vcpu time info region David Woodhouse
2021-01-11 19:57 ` [PATCH v5 13/16] KVM: x86/xen: register runstate info David Woodhouse
2021-01-28 12:15   ` Paolo Bonzini
2021-01-11 19:57 ` [PATCH v5 14/16] KVM: x86: declare Xen HVM shared info capability and add test case David Woodhouse
2021-01-18 14:06   ` [KVM] 19b4a47436: WARNING:suspicious_RCU_usage kernel test robot
2021-01-18 14:06     ` kernel test robot
2021-01-11 19:57 ` [PATCH v5 15/16] KVM: Add documentation for Xen hypercall and shared_info updates David Woodhouse
2021-01-28 12:18   ` Paolo Bonzini
2021-01-28 16:49     ` David Woodhouse
2021-01-28 17:06       ` Paolo Bonzini
     [not found]         ` <f9b2b4e613ea4e6dd1f253f5092254d121c93c07.camel@infradead.org>
2021-01-29  7:59           ` Paolo Bonzini
2021-01-11 19:57 ` [PATCH v5 16/16] KVM: x86/xen: Add event channel interrupt vector upcall David Woodhouse
2021-01-28 12:43   ` Paolo Bonzini
2021-01-28 15:35     ` David Woodhouse
2021-01-28 17:01       ` Paolo Bonzini
2021-01-29 17:33     ` David Woodhouse
2021-01-29 19:19       ` Paolo Bonzini [this message]
2021-01-30 13:01         ` David Woodhouse
2021-01-21 11:56 ` [PATCH v5 17/16] KVM: x86/xen: Fix initialisation of gfn caches for Xen shared pages David Woodhouse
2021-01-28 12:45 ` [PATCH v5 00/16] KVM: Add minimal support for Xen HVM guests Paolo Bonzini

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