From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoffer Dall Subject: Re: [PATCH v5 07/22] KVM: arm64: vgic-its: Implement vgic_its_has_attr_regs and attr_regs_access Date: Thu, 27 Apr 2017 04:00:03 -0700 Message-ID: <20170427110003.GG50776@lvm> References: <1492164934-988-1-git-send-email-eric.auger@redhat.com> <1492164934-988-8-git-send-email-eric.auger@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: eric.auger.pro@gmail.com, marc.zyngier@arm.com, andre.przywara@arm.com, vijayak@caviumnetworks.com, Vijaya.Kumar@cavium.com, peter.maydell@linaro.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org, Prasun.Kapoor@cavium.com, drjones@redhat.com, pbonzini@redhat.com, dgilbert@redhat.com, quintela@redhat.com To: Eric Auger Return-path: Received: from mail-wm0-f48.google.com ([74.125.82.48]:38390 "EHLO mail-wm0-f48.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965199AbdD0LAG (ORCPT ); Thu, 27 Apr 2017 07:00:06 -0400 Received: by mail-wm0-f48.google.com with SMTP id r190so14658651wme.1 for ; Thu, 27 Apr 2017 04:00:06 -0700 (PDT) Content-Disposition: inline In-Reply-To: <1492164934-988-8-git-send-email-eric.auger@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: On Fri, Apr 14, 2017 at 12:15:19PM +0200, Eric Auger wrote: > This patch implements vgic_its_has_attr_regs and vgic_its_attr_regs_access > upon the MMIO framework. VGIC ITS KVM device KVM_DEV_ARM_VGIC_GRP_ITS_REGS > group becomes functional. > > At least GITS_CREADR and GITS_IIDR require to differentiate a guest write > action from a user access. As such let's introduce a new uaccess_its_write > vgic_register_region callback. > > Signed-off-by: Eric Auger > > --- > v4 -> v5: > - use GITS_TYPER instead of offset 0x8 > - uaccess_its_write now can return an error > > v3 -> v4: > - remove changes to the REGISTER_ITS_DESC macro. This will be handled in > subsequent patch with the introduction of a new REGISTER_ITS_DESC_UACCESS > macro > - fix IIDR access and add a comment wrt full length access > - handle endianness > - add kvm lock and vcpus lock > --- > virt/kvm/arm/vgic/vgic-its.c | 79 +++++++++++++++++++++++++++++++++++++++++-- > virt/kvm/arm/vgic/vgic-mmio.h | 9 +++-- > 2 files changed, 84 insertions(+), 4 deletions(-) > > diff --git a/virt/kvm/arm/vgic/vgic-its.c b/virt/kvm/arm/vgic/vgic-its.c > index f687e91..a9a2c12 100644 > --- a/virt/kvm/arm/vgic/vgic-its.c > +++ b/virt/kvm/arm/vgic/vgic-its.c > @@ -1469,14 +1469,89 @@ static void vgic_its_destroy(struct kvm_device *kvm_dev) > int vgic_its_has_attr_regs(struct kvm_device *dev, > struct kvm_device_attr *attr) > { > - return -ENXIO; > + const struct vgic_register_region *region; > + struct vgic_io_device iodev = { > + .regions = its_registers, > + .nr_regions = ARRAY_SIZE(its_registers), > + }; > + gpa_t offset = attr->attr; > + > + region = vgic_find_mmio_region(iodev.regions, > + iodev.nr_regions, > + offset); why do you need to define the iodev here? Can't you just pass its_registers and ARRAY_SIZE(its_registers) directly? > + if (!region) > + return -ENXIO; > + > + return 0; > } > > int vgic_its_attr_regs_access(struct kvm_device *dev, > struct kvm_device_attr *attr, > u64 *reg, bool is_write) > { > - return -ENXIO; > + const struct vgic_register_region *region; > + struct vgic_io_device iodev = { > + .regions = its_registers, > + .nr_regions = ARRAY_SIZE(its_registers), > + }; > + struct vgic_its *its = dev->private; > + gpa_t addr, offset = attr->attr; > + unsigned int len; > + unsigned long data = 0; > + int ret = 0; nit: you could structure this whole declaration block more nicely by having a separate line for the declaration and initialization of offset, and by moving the iodev declaration/initialization to the end. It might also be cleaner to do any non-zero initialization in a separate block following the declarations. > + > + /* > + * Among supported registers, only GITS_CTLR (0x0) and GITS_IIDR (0x4) > + * are 32 bits. Others are 64 bits. > + */ > + if ((offset < GITS_TYPER && offset & 0x3) || > + (offset >= GITS_TYPER && offset & 0x7)) > + return -EINVAL; > + > + mutex_lock(&dev->kvm->lock); > + > + if (IS_VGIC_ADDR_UNDEF(its->vgic_its_base)) { > + ret = -ENXIO; > + goto out; > + } > + > + region = vgic_find_mmio_region(iodev.regions, > + iodev.nr_regions, > + offset); > + if (!region) { > + ret = -ENXIO; > + goto out; > + } > + > + if (!lock_all_vcpus(dev->kvm)) { > + ret = -EBUSY; > + goto out; > + } > + > + addr = its->vgic_its_base + offset; > + > + /* > + * Only full length register accesses are supported although > + * the architecture spec theoretically allows upper/lower 32 does the spec allow 32-bit accesses, or only theoretically ? :) > + * bits to be accessed independently > + */ In any case, the comment is a bit confusing, because it seems to imply that we only support 64-bit accesses, but we do set the length below to 4 or 8. Did you mean: /* * Althought the spec supports upper/lower 32-bit accesses to * 64-bit ITS registers, the userspace ABI requires 64-bit * accesses to all 64-bit wide registers. We therefore only 32-bit * accesses to the GITS_CTLR, GITS_IIDR registers. */ Also, I don't understand how this works with the ID registers? For example, if userspace wants to read GITS_PIDR1 does it have to read GITS_PIDR0 as a 64-bit register and split it afterwards? (that doesn't work with this implementation) > + len = region->access_flags & VGIC_ACCESS_64bit ? 8 : 4; > + > + if (is_write) { > + data = vgic_data_mmio_bus_to_host(reg, len); I don't think we need this anymore; we no longer share the guest trapping MMIO path with uaccesses. > + if (region->uaccess_its_write) > + ret = region->uaccess_its_write(dev->kvm, its, addr, > + len, data); > + else > + region->its_write(dev->kvm, its, addr, len, data); > + } else { > + data = region->its_read(dev->kvm, its, addr, len); > + vgic_data_host_to_mmio_bus(reg, len, data); same here. > + } > + unlock_all_vcpus(dev->kvm); > +out: > + mutex_unlock(&dev->kvm->lock); > + return ret; > } > > static int vgic_its_has_attr(struct kvm_device *dev, > diff --git a/virt/kvm/arm/vgic/vgic-mmio.h b/virt/kvm/arm/vgic/vgic-mmio.h > index 6eec91b..ea4171a 100644 > --- a/virt/kvm/arm/vgic/vgic-mmio.h > +++ b/virt/kvm/arm/vgic/vgic-mmio.h > @@ -36,8 +36,13 @@ struct vgic_register_region { > }; > unsigned long (*uaccess_read)(struct kvm_vcpu *vcpu, gpa_t addr, > unsigned int len); > - void (*uaccess_write)(struct kvm_vcpu *vcpu, gpa_t addr, > - unsigned int len, unsigned long val); > + union { > + void (*uaccess_write)(struct kvm_vcpu *vcpu, gpa_t addr, > + unsigned int len, unsigned long val); > + int (*uaccess_its_write)(struct kvm *kvm, struct vgic_its *its, > + gpa_t addr, unsigned int len, > + unsigned long val); > + }; > }; > > extern struct kvm_io_device_ops kvm_io_gic_ops; > -- > 2.5.5 > Thanks, -Christoffer From mboxrd@z Thu Jan 1 00:00:00 1970 From: christoffer.dall@linaro.org (Christoffer Dall) Date: Thu, 27 Apr 2017 04:00:03 -0700 Subject: [PATCH v5 07/22] KVM: arm64: vgic-its: Implement vgic_its_has_attr_regs and attr_regs_access In-Reply-To: <1492164934-988-8-git-send-email-eric.auger@redhat.com> References: <1492164934-988-1-git-send-email-eric.auger@redhat.com> <1492164934-988-8-git-send-email-eric.auger@redhat.com> Message-ID: <20170427110003.GG50776@lvm> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Fri, Apr 14, 2017 at 12:15:19PM +0200, Eric Auger wrote: > This patch implements vgic_its_has_attr_regs and vgic_its_attr_regs_access > upon the MMIO framework. VGIC ITS KVM device KVM_DEV_ARM_VGIC_GRP_ITS_REGS > group becomes functional. > > At least GITS_CREADR and GITS_IIDR require to differentiate a guest write > action from a user access. As such let's introduce a new uaccess_its_write > vgic_register_region callback. > > Signed-off-by: Eric Auger > > --- > v4 -> v5: > - use GITS_TYPER instead of offset 0x8 > - uaccess_its_write now can return an error > > v3 -> v4: > - remove changes to the REGISTER_ITS_DESC macro. This will be handled in > subsequent patch with the introduction of a new REGISTER_ITS_DESC_UACCESS > macro > - fix IIDR access and add a comment wrt full length access > - handle endianness > - add kvm lock and vcpus lock > --- > virt/kvm/arm/vgic/vgic-its.c | 79 +++++++++++++++++++++++++++++++++++++++++-- > virt/kvm/arm/vgic/vgic-mmio.h | 9 +++-- > 2 files changed, 84 insertions(+), 4 deletions(-) > > diff --git a/virt/kvm/arm/vgic/vgic-its.c b/virt/kvm/arm/vgic/vgic-its.c > index f687e91..a9a2c12 100644 > --- a/virt/kvm/arm/vgic/vgic-its.c > +++ b/virt/kvm/arm/vgic/vgic-its.c > @@ -1469,14 +1469,89 @@ static void vgic_its_destroy(struct kvm_device *kvm_dev) > int vgic_its_has_attr_regs(struct kvm_device *dev, > struct kvm_device_attr *attr) > { > - return -ENXIO; > + const struct vgic_register_region *region; > + struct vgic_io_device iodev = { > + .regions = its_registers, > + .nr_regions = ARRAY_SIZE(its_registers), > + }; > + gpa_t offset = attr->attr; > + > + region = vgic_find_mmio_region(iodev.regions, > + iodev.nr_regions, > + offset); why do you need to define the iodev here? Can't you just pass its_registers and ARRAY_SIZE(its_registers) directly? > + if (!region) > + return -ENXIO; > + > + return 0; > } > > int vgic_its_attr_regs_access(struct kvm_device *dev, > struct kvm_device_attr *attr, > u64 *reg, bool is_write) > { > - return -ENXIO; > + const struct vgic_register_region *region; > + struct vgic_io_device iodev = { > + .regions = its_registers, > + .nr_regions = ARRAY_SIZE(its_registers), > + }; > + struct vgic_its *its = dev->private; > + gpa_t addr, offset = attr->attr; > + unsigned int len; > + unsigned long data = 0; > + int ret = 0; nit: you could structure this whole declaration block more nicely by having a separate line for the declaration and initialization of offset, and by moving the iodev declaration/initialization to the end. It might also be cleaner to do any non-zero initialization in a separate block following the declarations. > + > + /* > + * Among supported registers, only GITS_CTLR (0x0) and GITS_IIDR (0x4) > + * are 32 bits. Others are 64 bits. > + */ > + if ((offset < GITS_TYPER && offset & 0x3) || > + (offset >= GITS_TYPER && offset & 0x7)) > + return -EINVAL; > + > + mutex_lock(&dev->kvm->lock); > + > + if (IS_VGIC_ADDR_UNDEF(its->vgic_its_base)) { > + ret = -ENXIO; > + goto out; > + } > + > + region = vgic_find_mmio_region(iodev.regions, > + iodev.nr_regions, > + offset); > + if (!region) { > + ret = -ENXIO; > + goto out; > + } > + > + if (!lock_all_vcpus(dev->kvm)) { > + ret = -EBUSY; > + goto out; > + } > + > + addr = its->vgic_its_base + offset; > + > + /* > + * Only full length register accesses are supported although > + * the architecture spec theoretically allows upper/lower 32 does the spec allow 32-bit accesses, or only theoretically ? :) > + * bits to be accessed independently > + */ In any case, the comment is a bit confusing, because it seems to imply that we only support 64-bit accesses, but we do set the length below to 4 or 8. Did you mean: /* * Althought the spec supports upper/lower 32-bit accesses to * 64-bit ITS registers, the userspace ABI requires 64-bit * accesses to all 64-bit wide registers. We therefore only 32-bit * accesses to the GITS_CTLR, GITS_IIDR registers. */ Also, I don't understand how this works with the ID registers? For example, if userspace wants to read GITS_PIDR1 does it have to read GITS_PIDR0 as a 64-bit register and split it afterwards? (that doesn't work with this implementation) > + len = region->access_flags & VGIC_ACCESS_64bit ? 8 : 4; > + > + if (is_write) { > + data = vgic_data_mmio_bus_to_host(reg, len); I don't think we need this anymore; we no longer share the guest trapping MMIO path with uaccesses. > + if (region->uaccess_its_write) > + ret = region->uaccess_its_write(dev->kvm, its, addr, > + len, data); > + else > + region->its_write(dev->kvm, its, addr, len, data); > + } else { > + data = region->its_read(dev->kvm, its, addr, len); > + vgic_data_host_to_mmio_bus(reg, len, data); same here. > + } > + unlock_all_vcpus(dev->kvm); > +out: > + mutex_unlock(&dev->kvm->lock); > + return ret; > } > > static int vgic_its_has_attr(struct kvm_device *dev, > diff --git a/virt/kvm/arm/vgic/vgic-mmio.h b/virt/kvm/arm/vgic/vgic-mmio.h > index 6eec91b..ea4171a 100644 > --- a/virt/kvm/arm/vgic/vgic-mmio.h > +++ b/virt/kvm/arm/vgic/vgic-mmio.h > @@ -36,8 +36,13 @@ struct vgic_register_region { > }; > unsigned long (*uaccess_read)(struct kvm_vcpu *vcpu, gpa_t addr, > unsigned int len); > - void (*uaccess_write)(struct kvm_vcpu *vcpu, gpa_t addr, > - unsigned int len, unsigned long val); > + union { > + void (*uaccess_write)(struct kvm_vcpu *vcpu, gpa_t addr, > + unsigned int len, unsigned long val); > + int (*uaccess_its_write)(struct kvm *kvm, struct vgic_its *its, > + gpa_t addr, unsigned int len, > + unsigned long val); > + }; > }; > > extern struct kvm_io_device_ops kvm_io_gic_ops; > -- > 2.5.5 > Thanks, -Christoffer