From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoffer Dall Subject: Re: [PATCH v4 06/10] KVM: arm: vgic: Support 64-bit data manipulation on 32-bit host systems Date: Tue, 13 Sep 2016 10:51:58 +0200 Message-ID: <20160913085158.GG5680@cbox> References: <1473691764-29424-1-git-send-email-vladimir.murzin@arm.com> <1473691764-29424-7-git-send-email-vladimir.murzin@arm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from localhost (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 3BCCF49B7C for ; Tue, 13 Sep 2016 04:40:38 -0400 (EDT) Received: from mm01.cs.columbia.edu ([127.0.0.1]) by localhost (mm01.cs.columbia.edu [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id j1Vt8eiTw6A9 for ; Tue, 13 Sep 2016 04:40:37 -0400 (EDT) Received: from mail-wm0-f45.google.com (mail-wm0-f45.google.com [74.125.82.45]) by mm01.cs.columbia.edu (Postfix) with ESMTPS id 55A0B49B76 for ; Tue, 13 Sep 2016 04:40:37 -0400 (EDT) Received: by mail-wm0-f45.google.com with SMTP id 1so187956466wmz.1 for ; Tue, 13 Sep 2016 01:49:20 -0700 (PDT) Content-Disposition: inline In-Reply-To: <1473691764-29424-7-git-send-email-vladimir.murzin@arm.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: kvmarm-bounces@lists.cs.columbia.edu Sender: kvmarm-bounces@lists.cs.columbia.edu To: Vladimir Murzin Cc: marc.zyngier@arm.com, andre.przywara@arm.com, kvmarm@lists.cs.columbia.edu, linux-arm-kernel@lists.infradead.org List-Id: kvmarm@lists.cs.columbia.edu On Mon, Sep 12, 2016 at 03:49:20PM +0100, Vladimir Murzin wrote: > We have couple of 64-bit registers defined in GICv3 architecture, so > unsigned long accesses to these registers will only access a single > 32-bit part of that regitser. On the other hand these registers can't > be accessed as 64-bit with a single instruction like ldrd/strd or > ldmia/stmia if we run a 32-bit host because KVM does not support > access to MMIO space done by these instructions. > > It means that a 32-bit guest accesses these registers in 32-bit > chunks, so the only thing we need to do is to ensure that > extract_bytes() always takes 64-bit data. > > Signed-off-by: Vladimir Murzin Acked-by: Christoffer Dall > --- > virt/kvm/arm/vgic/vgic-mmio-v3.c | 2 +- > virt/kvm/arm/vgic/vgic-mmio.h | 2 +- > 2 files changed, 2 insertions(+), 2 deletions(-) > > diff --git a/virt/kvm/arm/vgic/vgic-mmio-v3.c b/virt/kvm/arm/vgic/vgic-mmio-v3.c > index 6385ed5..0d3c76a 100644 > --- a/virt/kvm/arm/vgic/vgic-mmio-v3.c > +++ b/virt/kvm/arm/vgic/vgic-mmio-v3.c > @@ -23,7 +23,7 @@ > #include "vgic-mmio.h" > > /* extract @num bytes at @offset bytes offset in data */ > -unsigned long extract_bytes(unsigned long data, unsigned int offset, > +unsigned long extract_bytes(u64 data, unsigned int offset, > unsigned int num) > { > return (data >> (offset * 8)) & GENMASK_ULL(num * 8 - 1, 0); > diff --git a/virt/kvm/arm/vgic/vgic-mmio.h b/virt/kvm/arm/vgic/vgic-mmio.h > index 0b3ecf9..80f92ce 100644 > --- a/virt/kvm/arm/vgic/vgic-mmio.h > +++ b/virt/kvm/arm/vgic/vgic-mmio.h > @@ -96,7 +96,7 @@ unsigned long vgic_data_mmio_bus_to_host(const void *val, unsigned int len); > void vgic_data_host_to_mmio_bus(void *buf, unsigned int len, > unsigned long data); > > -unsigned long extract_bytes(unsigned long data, unsigned int offset, > +unsigned long extract_bytes(u64 data, unsigned int offset, > unsigned int num); > > u64 update_64bit_reg(u64 reg, unsigned int offset, unsigned int len, > -- > 1.7.9.5 > From mboxrd@z Thu Jan 1 00:00:00 1970 From: christoffer.dall@linaro.org (Christoffer Dall) Date: Tue, 13 Sep 2016 10:51:58 +0200 Subject: [PATCH v4 06/10] KVM: arm: vgic: Support 64-bit data manipulation on 32-bit host systems In-Reply-To: <1473691764-29424-7-git-send-email-vladimir.murzin@arm.com> References: <1473691764-29424-1-git-send-email-vladimir.murzin@arm.com> <1473691764-29424-7-git-send-email-vladimir.murzin@arm.com> Message-ID: <20160913085158.GG5680@cbox> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Mon, Sep 12, 2016 at 03:49:20PM +0100, Vladimir Murzin wrote: > We have couple of 64-bit registers defined in GICv3 architecture, so > unsigned long accesses to these registers will only access a single > 32-bit part of that regitser. On the other hand these registers can't > be accessed as 64-bit with a single instruction like ldrd/strd or > ldmia/stmia if we run a 32-bit host because KVM does not support > access to MMIO space done by these instructions. > > It means that a 32-bit guest accesses these registers in 32-bit > chunks, so the only thing we need to do is to ensure that > extract_bytes() always takes 64-bit data. > > Signed-off-by: Vladimir Murzin Acked-by: Christoffer Dall > --- > virt/kvm/arm/vgic/vgic-mmio-v3.c | 2 +- > virt/kvm/arm/vgic/vgic-mmio.h | 2 +- > 2 files changed, 2 insertions(+), 2 deletions(-) > > diff --git a/virt/kvm/arm/vgic/vgic-mmio-v3.c b/virt/kvm/arm/vgic/vgic-mmio-v3.c > index 6385ed5..0d3c76a 100644 > --- a/virt/kvm/arm/vgic/vgic-mmio-v3.c > +++ b/virt/kvm/arm/vgic/vgic-mmio-v3.c > @@ -23,7 +23,7 @@ > #include "vgic-mmio.h" > > /* extract @num bytes at @offset bytes offset in data */ > -unsigned long extract_bytes(unsigned long data, unsigned int offset, > +unsigned long extract_bytes(u64 data, unsigned int offset, > unsigned int num) > { > return (data >> (offset * 8)) & GENMASK_ULL(num * 8 - 1, 0); > diff --git a/virt/kvm/arm/vgic/vgic-mmio.h b/virt/kvm/arm/vgic/vgic-mmio.h > index 0b3ecf9..80f92ce 100644 > --- a/virt/kvm/arm/vgic/vgic-mmio.h > +++ b/virt/kvm/arm/vgic/vgic-mmio.h > @@ -96,7 +96,7 @@ unsigned long vgic_data_mmio_bus_to_host(const void *val, unsigned int len); > void vgic_data_host_to_mmio_bus(void *buf, unsigned int len, > unsigned long data); > > -unsigned long extract_bytes(unsigned long data, unsigned int offset, > +unsigned long extract_bytes(u64 data, unsigned int offset, > unsigned int num); > > u64 update_64bit_reg(u64 reg, unsigned int offset, unsigned int len, > -- > 1.7.9.5 >