From mboxrd@z Thu Jan 1 00:00:00 1970 From: vladimir.murzin@arm.com (Vladimir Murzin) Date: Mon, 12 Sep 2016 15:49:20 +0100 Subject: [PATCH v4 06/10] KVM: arm: vgic: Support 64-bit data manipulation on 32-bit host systems In-Reply-To: <1473691764-29424-1-git-send-email-vladimir.murzin@arm.com> References: <1473691764-29424-1-git-send-email-vladimir.murzin@arm.com> Message-ID: <1473691764-29424-7-git-send-email-vladimir.murzin@arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org 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 --- 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