[PATCH v6 1/7] arm/arm64: vgic-new: Implement support for userspace access
Marc Zyngier
marc.zyngier at arm.com
Thu Sep 22 05:08:56 PDT 2016
On 20/09/16 07:12, vijay.kilari at gmail.com wrote:
> From: Vijaya Kumar K <Vijaya.Kumar at cavium.com>
>
> Read and write of some registers like ISPENDR and ICPENDR
> from userspace requires special handling when compared to
> guest access for these registers.
>
> Refer to Documentation/virtual/kvm/devices/arm-vgic-v3.txt
> for handling of ISPENDR, ICPENDR registers handling.
>
> Add infrastructure to support guest and userspace read
> and write for the required registers
> Also moved vgic_uaccess from vgic-mmio-v2.c to vgic-mmio.c
>
> Signed-off-by: Vijaya Kumar K <Vijaya.Kumar at cavium.com>
> ---
> virt/kvm/arm/vgic/vgic-mmio-v2.c | 25 ----------
> virt/kvm/arm/vgic/vgic-mmio-v3.c | 98 ++++++++++++++++++++++++++++++++--------
> virt/kvm/arm/vgic/vgic-mmio.c | 78 ++++++++++++++++++++++++++++----
> virt/kvm/arm/vgic/vgic-mmio.h | 19 ++++++++
> 4 files changed, 169 insertions(+), 51 deletions(-)
>
> diff --git a/virt/kvm/arm/vgic/vgic-mmio-v2.c b/virt/kvm/arm/vgic/vgic-mmio-v2.c
> index b44b359..0b32f40 100644
> --- a/virt/kvm/arm/vgic/vgic-mmio-v2.c
> +++ b/virt/kvm/arm/vgic/vgic-mmio-v2.c
> @@ -406,31 +406,6 @@ int vgic_v2_has_attr_regs(struct kvm_device *dev, struct kvm_device_attr *attr)
> return -ENXIO;
> }
>
> -/*
> - * When userland tries to access the VGIC register handlers, we need to
> - * create a usable struct vgic_io_device to be passed to the handlers and we
> - * have to set up a buffer similar to what would have happened if a guest MMIO
> - * access occurred, including doing endian conversions on BE systems.
> - */
> -static int vgic_uaccess(struct kvm_vcpu *vcpu, struct vgic_io_device *dev,
> - bool is_write, int offset, u32 *val)
> -{
> - unsigned int len = 4;
> - u8 buf[4];
> - int ret;
> -
> - if (is_write) {
> - vgic_data_host_to_mmio_bus(buf, len, *val);
> - ret = kvm_io_gic_ops.write(vcpu, &dev->dev, offset, len, buf);
> - } else {
> - ret = kvm_io_gic_ops.read(vcpu, &dev->dev, offset, len, buf);
> - if (!ret)
> - *val = vgic_data_mmio_bus_to_host(buf, len);
> - }
> -
> - return ret;
> -}
> -
> int vgic_v2_cpuif_uaccess(struct kvm_vcpu *vcpu, bool is_write,
> int offset, u32 *val)
> {
> diff --git a/virt/kvm/arm/vgic/vgic-mmio-v3.c b/virt/kvm/arm/vgic/vgic-mmio-v3.c
> index 0d3c76a..ce2708d 100644
> --- a/virt/kvm/arm/vgic/vgic-mmio-v3.c
> +++ b/virt/kvm/arm/vgic/vgic-mmio-v3.c
> @@ -209,6 +209,62 @@ static unsigned long vgic_mmio_read_v3_idregs(struct kvm_vcpu *vcpu,
> return 0;
> }
>
> +static unsigned long vgic_v3_uaccess_read_pending(struct kvm_vcpu *vcpu,
> + gpa_t addr, unsigned int len)
> +{
> + u32 intid = VGIC_ADDR_TO_INTID(addr, 1);
> + u32 value = 0;
> + int i;
> +
> + /*
> + * A level triggerred interrupt pending state is latched in both
> + * "soft_pending" and "line_level" variables. Userspace will save
> + * and restore soft_pending and line_level separately.
> + * Refer to Documentation/virtual/kvm/devices/arm-vgic-v3.txt
> + * handling of ISPENDR and ICPENDR.
> + */
> + for (i = 0; i < len * 8; i++) {
> + struct vgic_irq *irq = vgic_get_irq(vcpu->kvm, vcpu, intid + i);
> +
> + if (irq->config == VGIC_CONFIG_LEVEL && irq->soft_pending)
> + value |= (1U << i);
> + if (irq->config == VGIC_CONFIG_EDGE && irq->pending)
> + value |= (1U << i);
> +
> + vgic_put_irq(vcpu->kvm, irq);
> + }
> +
> + return value;
> +}
> +
> +static void vgic_v3_uaccess_write_pending(struct kvm_vcpu *vcpu,
> + gpa_t addr, unsigned int len,
> + unsigned long val)
> +{
> + u32 intid = VGIC_ADDR_TO_INTID(addr, 1);
> + int i;
> +
> + for (i = 0; i < len * 8; i++) {
> + struct vgic_irq *irq = vgic_get_irq(vcpu->kvm, vcpu, intid + i);
> +
> + spin_lock(&irq->irq_lock);
> + if (test_bit(i, &val)) {
> + irq->pending = true;
> + irq->soft_pending = true;
> + vgic_queue_irq_unlock(vcpu->kvm, irq);
> + } else {
> + irq->soft_pending = false;
> + if (irq->config == VGIC_CONFIG_EDGE ||
> + (irq->config == VGIC_CONFIG_LEVEL &&
> + !irq->line_level))
> + irq->pending = false;
> + spin_unlock(&irq->irq_lock);
> + }
> +
> + vgic_put_irq(vcpu->kvm, irq);
> + }
> +}
> +
> /* We want to avoid outer shareable. */
> u64 vgic_sanitise_shareability(u64 field)
> {
> @@ -358,7 +414,7 @@ static void vgic_mmio_write_pendbase(struct kvm_vcpu *vcpu,
> * We take some special care here to fix the calculation of the register
> * offset.
> */
> -#define REGISTER_DESC_WITH_BITS_PER_IRQ_SHARED(off, rd, wr, bpi, acc) \
> +#define REGISTER_DESC_WITH_BITS_PER_IRQ_SHARED(off, rd, wr, ur, uw, bpi, acc) \
> { \
> .reg_offset = off, \
> .bits_per_irq = bpi, \
> @@ -373,6 +429,8 @@ static void vgic_mmio_write_pendbase(struct kvm_vcpu *vcpu,
> .access_flags = acc, \
> .read = rd, \
> .write = wr, \
> + .uaccess_read = ur, \
> + .uaccess_write = uw, \
> }
>
> static const struct vgic_register_region vgic_v3_dist_registers[] = {
> @@ -380,40 +438,42 @@ static const struct vgic_register_region vgic_v3_dist_registers[] = {
> vgic_mmio_read_v3_misc, vgic_mmio_write_v3_misc, 16,
> VGIC_ACCESS_32bit),
> REGISTER_DESC_WITH_BITS_PER_IRQ_SHARED(GICD_IGROUPR,
> - vgic_mmio_read_rao, vgic_mmio_write_wi, 1,
> + vgic_mmio_read_rao, vgic_mmio_write_wi, NULL, NULL, 1,
> VGIC_ACCESS_32bit),
> REGISTER_DESC_WITH_BITS_PER_IRQ_SHARED(GICD_ISENABLER,
> - vgic_mmio_read_enable, vgic_mmio_write_senable, 1,
> + vgic_mmio_read_enable, vgic_mmio_write_senable, NULL, NULL, 1,
> VGIC_ACCESS_32bit),
> REGISTER_DESC_WITH_BITS_PER_IRQ_SHARED(GICD_ICENABLER,
> - vgic_mmio_read_enable, vgic_mmio_write_cenable, 1,
> + vgic_mmio_read_enable, vgic_mmio_write_cenable, NULL, NULL, 1,
> VGIC_ACCESS_32bit),
> REGISTER_DESC_WITH_BITS_PER_IRQ_SHARED(GICD_ISPENDR,
> - vgic_mmio_read_pending, vgic_mmio_write_spending, 1,
> + vgic_mmio_read_pending, vgic_mmio_write_spending,
> + vgic_v3_uaccess_read_pending, vgic_v3_uaccess_write_pending, 1,
> VGIC_ACCESS_32bit),
> REGISTER_DESC_WITH_BITS_PER_IRQ_SHARED(GICD_ICPENDR,
> - vgic_mmio_read_pending, vgic_mmio_write_cpending, 1,
> + vgic_mmio_read_pending, vgic_mmio_write_cpending,
> + vgic_mmio_read_raz, vgic_mmio_write_wi, 1,
> VGIC_ACCESS_32bit),
> REGISTER_DESC_WITH_BITS_PER_IRQ_SHARED(GICD_ISACTIVER,
> - vgic_mmio_read_active, vgic_mmio_write_sactive, 1,
> + vgic_mmio_read_active, vgic_mmio_write_sactive, NULL, NULL, 1,
> VGIC_ACCESS_32bit),
> REGISTER_DESC_WITH_BITS_PER_IRQ_SHARED(GICD_ICACTIVER,
> - vgic_mmio_read_active, vgic_mmio_write_cactive, 1,
> + vgic_mmio_read_active, vgic_mmio_write_cactive, NULL, NULL, 1,
> VGIC_ACCESS_32bit),
> REGISTER_DESC_WITH_BITS_PER_IRQ_SHARED(GICD_IPRIORITYR,
> - vgic_mmio_read_priority, vgic_mmio_write_priority, 8,
> - VGIC_ACCESS_32bit | VGIC_ACCESS_8bit),
> + vgic_mmio_read_priority, vgic_mmio_write_priority, NULL, NULL,
> + 8, VGIC_ACCESS_32bit | VGIC_ACCESS_8bit),
> REGISTER_DESC_WITH_BITS_PER_IRQ_SHARED(GICD_ITARGETSR,
> - vgic_mmio_read_raz, vgic_mmio_write_wi, 8,
> + vgic_mmio_read_raz, vgic_mmio_write_wi, NULL, NULL, 8,
> VGIC_ACCESS_32bit | VGIC_ACCESS_8bit),
> REGISTER_DESC_WITH_BITS_PER_IRQ_SHARED(GICD_ICFGR,
> - vgic_mmio_read_config, vgic_mmio_write_config, 2,
> + vgic_mmio_read_config, vgic_mmio_write_config, NULL, NULL, 2,
> VGIC_ACCESS_32bit),
> REGISTER_DESC_WITH_BITS_PER_IRQ_SHARED(GICD_IGRPMODR,
> - vgic_mmio_read_raz, vgic_mmio_write_wi, 1,
> + vgic_mmio_read_raz, vgic_mmio_write_wi, NULL, NULL, 1,
> VGIC_ACCESS_32bit),
> REGISTER_DESC_WITH_BITS_PER_IRQ_SHARED(GICD_IROUTER,
> - vgic_mmio_read_irouter, vgic_mmio_write_irouter, 64,
> + vgic_mmio_read_irouter, vgic_mmio_write_irouter, NULL, NULL, 64,
> VGIC_ACCESS_64bit | VGIC_ACCESS_32bit),
> REGISTER_DESC_WITH_LENGTH(GICD_IDREGS,
> vgic_mmio_read_v3_idregs, vgic_mmio_write_wi, 48,
> @@ -451,11 +511,13 @@ static const struct vgic_register_region vgic_v3_sgibase_registers[] = {
> REGISTER_DESC_WITH_LENGTH(GICR_ICENABLER0,
> vgic_mmio_read_enable, vgic_mmio_write_cenable, 4,
> VGIC_ACCESS_32bit),
> - REGISTER_DESC_WITH_LENGTH(GICR_ISPENDR0,
> - vgic_mmio_read_pending, vgic_mmio_write_spending, 4,
> + REGISTER_DESC_WITH_LENGTH_UACCESS(GICR_ISPENDR0,
> + vgic_mmio_read_pending, vgic_mmio_write_spending,
> + vgic_v3_uaccess_read_pending, vgic_v3_uaccess_write_pending, 4,
> VGIC_ACCESS_32bit),
> - REGISTER_DESC_WITH_LENGTH(GICR_ICPENDR0,
> - vgic_mmio_read_pending, vgic_mmio_write_cpending, 4,
> + REGISTER_DESC_WITH_LENGTH_UACCESS(GICR_ICPENDR0,
> + vgic_mmio_read_pending, vgic_mmio_write_cpending,
> + vgic_mmio_read_raz, vgic_mmio_write_wi, 4,
> VGIC_ACCESS_32bit),
> REGISTER_DESC_WITH_LENGTH(GICR_ISACTIVER0,
> vgic_mmio_read_active, vgic_mmio_write_sactive, 4,
> diff --git a/virt/kvm/arm/vgic/vgic-mmio.c b/virt/kvm/arm/vgic/vgic-mmio.c
> index e18b30d..31f85df 100644
> --- a/virt/kvm/arm/vgic/vgic-mmio.c
> +++ b/virt/kvm/arm/vgic/vgic-mmio.c
> @@ -468,6 +468,73 @@ static bool check_region(const struct vgic_register_region *region,
> return false;
> }
>
> +static const struct vgic_register_region *
> +vgic_get_mmio_region(struct vgic_io_device *iodev, gpa_t addr, int len)
> +{
> + const struct vgic_register_region *region;
> +
> + region = vgic_find_mmio_region(iodev->regions, iodev->nr_regions,
> + addr - iodev->base_addr);
> + if (!region || !check_region(region, addr, len))
> + return NULL;
> +
> + return region;
> +}
> +
> +static int vgic_uaccess_read(struct kvm_vcpu *vcpu, struct kvm_io_device *dev,
> + gpa_t addr, u32 *val)
> +{
> + struct vgic_io_device *iodev = kvm_to_vgic_iodev(dev);
> + const struct vgic_register_region *region;
> + struct kvm_vcpu *r_vcpu;
> +
> + region = vgic_get_mmio_region(iodev, addr, sizeof(u32));
> + if (!region) {
> + *val = 0;
> + return 0;
This is not the previous semantic of vgic_uaccess, and I cannot see why
blindly ignoring an access to an undefined region would be acceptable.
What am I missing?
> + }
> +
> + r_vcpu = iodev->redist_vcpu ? iodev->redist_vcpu : vcpu;
> + if (region->uaccess_read)
> + *val = region->uaccess_read(r_vcpu, addr, sizeof(u32));
> + else
> + *val = region->read(r_vcpu, addr, sizeof(u32));
> +
> + return 0;
> +}
> +
> +static int vgic_uaccess_write(struct kvm_vcpu *vcpu, struct kvm_io_device *dev,
> + gpa_t addr, const u32 *val)
> +{
> + struct vgic_io_device *iodev = kvm_to_vgic_iodev(dev);
> + const struct vgic_register_region *region;
> + struct kvm_vcpu *r_vcpu;
> +
> + region = vgic_get_mmio_region(iodev, addr, sizeof(u32));
> + if (!region)
> + return 0;
Same here.
> +
> + r_vcpu = iodev->redist_vcpu ? iodev->redist_vcpu : vcpu;
> + if (region->uaccess_write)
> + region->uaccess_write(r_vcpu, addr, sizeof(u32), *val);
> + else
> + region->write(r_vcpu, addr, sizeof(u32), *val);
> +
> + return 0;
> +}
> +
> +/*
> + * Userland access to VGIC registers.
> + */
> +int vgic_uaccess(struct kvm_vcpu *vcpu, struct vgic_io_device *dev,
> + bool is_write, int offset, u32 *val)
> +{
> + if (is_write)
> + return vgic_uaccess_write(vcpu, &dev->dev, offset, val);
> + else
> + return vgic_uaccess_read(vcpu, &dev->dev, offset, val);
> +}
> +
> static int dispatch_mmio_read(struct kvm_vcpu *vcpu, struct kvm_io_device *dev,
> gpa_t addr, int len, void *val)
> {
> @@ -475,9 +542,8 @@ static int dispatch_mmio_read(struct kvm_vcpu *vcpu, struct kvm_io_device *dev,
> const struct vgic_register_region *region;
> unsigned long data = 0;
>
> - region = vgic_find_mmio_region(iodev->regions, iodev->nr_regions,
> - addr - iodev->base_addr);
> - if (!region || !check_region(region, addr, len)) {
> + region = vgic_get_mmio_region(iodev, addr, len);
> + if (!region) {
> memset(val, 0, len);
> return 0;
> }
> @@ -508,14 +574,10 @@ static int dispatch_mmio_write(struct kvm_vcpu *vcpu, struct kvm_io_device *dev,
> const struct vgic_register_region *region;
> unsigned long data = vgic_data_mmio_bus_to_host(val, len);
>
> - region = vgic_find_mmio_region(iodev->regions, iodev->nr_regions,
> - addr - iodev->base_addr);
> + region = vgic_get_mmio_region(iodev, addr, len);
> if (!region)
> return 0;
>
> - if (!check_region(region, addr, len))
> - return 0;
> -
> switch (iodev->iodev_type) {
> case IODEV_CPUIF:
> region->write(vcpu, addr, len, data);
> diff --git a/virt/kvm/arm/vgic/vgic-mmio.h b/virt/kvm/arm/vgic/vgic-mmio.h
> index 4c34d39..97e6df7 100644
> --- a/virt/kvm/arm/vgic/vgic-mmio.h
> +++ b/virt/kvm/arm/vgic/vgic-mmio.h
> @@ -34,6 +34,10 @@ struct vgic_register_region {
> gpa_t addr, unsigned int len,
> unsigned long val);
> };
> + 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);
> };
>
> extern struct kvm_io_device_ops kvm_io_gic_ops;
> @@ -86,6 +90,18 @@ extern struct kvm_io_device_ops kvm_io_gic_ops;
> .write = wr, \
> }
>
> +#define REGISTER_DESC_WITH_LENGTH_UACCESS(off, rd, wr, urd, uwr, length, acc) \
> + { \
> + .reg_offset = off, \
> + .bits_per_irq = 0, \
> + .len = length, \
> + .access_flags = acc, \
> + .read = rd, \
> + .write = wr, \
> + .uaccess_read = urd, \
> + .uaccess_write = uwr, \
> + }
> +
> int kvm_vgic_register_mmio_region(struct kvm *kvm, struct kvm_vcpu *vcpu,
> struct vgic_register_region *reg_desc,
> struct vgic_io_device *region,
> @@ -158,6 +174,9 @@ void vgic_mmio_write_config(struct kvm_vcpu *vcpu,
> gpa_t addr, unsigned int len,
> unsigned long val);
>
> +int vgic_uaccess(struct kvm_vcpu *vcpu, struct vgic_io_device *dev,
> + bool is_write, int offset, u32 *val);
> +
> unsigned int vgic_v2_init_dist_iodev(struct vgic_io_device *dev);
>
> unsigned int vgic_v3_init_dist_iodev(struct vgic_io_device *dev);
>
Thanks,
M.
--
Jazz is not dead. It just smells funny...
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