From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marc Zyngier Subject: Re: [PATCH v4 25/40] KVM: arm64: Introduce framework for accessing deferred sysregs Date: Wed, 21 Feb 2018 14:16:36 +0000 Message-ID: <868tbml96j.wl-marc.zyngier@arm.com> References: <20180215210332.8648-1-christoffer.dall@linaro.org> <20180215210332.8648-26-christoffer.dall@linaro.org> Mime-Version: 1.0 (generated by SEMI-EPG 1.14.7 - "Harue") Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: Andrew Jones , kvm@vger.kernel.org, Tomasz Nowicki , kvmarm@lists.cs.columbia.edu, Julien Grall , Yury Norov , linux-arm-kernel@lists.infradead.org, Dave Martin , Shih-Wei Li To: Christoffer Dall Return-path: In-Reply-To: <20180215210332.8648-26-christoffer.dall@linaro.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=m.gmane.org@lists.infradead.org List-Id: kvm.vger.kernel.org On Thu, 15 Feb 2018 21:03:17 +0000, Christoffer Dall wrote: > > We are about to defer saving and restoring some groups of system > registers to vcpu_put and vcpu_load on supported systems. This means > that we need some infrastructure to access system registes which > supports either accessing the memory backing of the register or directly > accessing the system registers, depending on the state of the system > when we access the register. > > We do this by defining read/write accessor functions, which can handle > both "immediate" and "deferrable" system registers. Immediate registers > are always saved/restored in the world-switch path, but deferrable > registers are only saved/restored in vcpu_put/vcpu_load when supported > and sysregs_loaded_on_cpu will be set in that case. > > Note that we don't use the deferred mechanism yet in this patch, but only > introduce infrastructure. This is to improve convenience of review in > the subsequent patches where it is clear which registers become > deferred. > > Signed-off-by: Christoffer Dall Reviewed-by: Marc Zyngier M. -- Jazz is not dead, it just smell funny. From mboxrd@z Thu Jan 1 00:00:00 1970 From: marc.zyngier@arm.com (Marc Zyngier) Date: Wed, 21 Feb 2018 14:16:36 +0000 Subject: [PATCH v4 25/40] KVM: arm64: Introduce framework for accessing deferred sysregs In-Reply-To: <20180215210332.8648-26-christoffer.dall@linaro.org> References: <20180215210332.8648-1-christoffer.dall@linaro.org> <20180215210332.8648-26-christoffer.dall@linaro.org> Message-ID: <868tbml96j.wl-marc.zyngier@arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Thu, 15 Feb 2018 21:03:17 +0000, Christoffer Dall wrote: > > We are about to defer saving and restoring some groups of system > registers to vcpu_put and vcpu_load on supported systems. This means > that we need some infrastructure to access system registes which > supports either accessing the memory backing of the register or directly > accessing the system registers, depending on the state of the system > when we access the register. > > We do this by defining read/write accessor functions, which can handle > both "immediate" and "deferrable" system registers. Immediate registers > are always saved/restored in the world-switch path, but deferrable > registers are only saved/restored in vcpu_put/vcpu_load when supported > and sysregs_loaded_on_cpu will be set in that case. > > Note that we don't use the deferred mechanism yet in this patch, but only > introduce infrastructure. This is to improve convenience of review in > the subsequent patches where it is clear which registers become > deferred. > > Signed-off-by: Christoffer Dall Reviewed-by: Marc Zyngier M. -- Jazz is not dead, it just smell funny.