Re: [PATCH v6 1/7] arm/arm64: vgic-new: Implement support for userspace access
On Fri, Sep 23, 2016 at 10:50:38AM +0100, Marc Zyngier wrote:
> On 22/09/16 15:01, Vijay Kilari wrote:
> > On Thu, Sep 22, 2016 at 5:38 PM, Marc Zyngier wrote:
> >> On 20/09/16 07:12, vijay.kil...@gmail.com wrote:
> >>> From: Vijaya Kumar K
> >>> +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?
> >
> > AFAIK, the vgic_uaccess is not making any check on undefined
> > region/register.
> > However, dispatch_mmio_read/write are returning 0 if check of region is
> > failed
>
> Hmmm. Fair enough. I don't really like it, but that's something for
> another day.
>
Agreed, we should raise an error in that case, but it's independent of
this series.
-Christoffer
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Re: [PATCH v6 1/7] arm/arm64: vgic-new: Implement support for userspace access
On 22/09/16 15:01, Vijay Kilari wrote:
> On Thu, Sep 22, 2016 at 5:38 PM, Marc Zyngier wrote:
>> On 20/09/16 07:12, vijay.kil...@gmail.com wrote:
>>> From: Vijaya Kumar K
>>> +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?
>
> AFAIK, the vgic_uaccess is not making any check on undefined region/register.
> However, dispatch_mmio_read/write are returning 0 if check of region is failed
Hmmm. Fair enough. I don't really like it, but that's something for
another day.
M.
--
Jazz is not dead. It just smells funny...
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Re: [PATCH v6 1/7] arm/arm64: vgic-new: Implement support for userspace access
On Thu, Sep 22, 2016 at 5:38 PM, Marc Zyngier wrote:
> On 20/09/16 07:12, vijay.kil...@gmail.com wrote:
>> From: Vijaya Kumar K
>>
>> 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
>> ---
>> 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)
>>
Re: [PATCH v6 1/7] arm/arm64: vgic-new: Implement support for userspace access
On 20/09/16 07:12, vijay.kil...@gmail.com wrote:
> From: Vijaya Kumar K
>
> 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
> ---
> 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.
> */
