[PATCH v5 22/22] KVM: arm64: vgic-v3: KVM_DEV_ARM_VGIC_SAVE_PENDING_TABLES
Christoffer Dall
christoffer.dall at linaro.org
Sun Apr 30 17:32:19 EDT 2017
On Fri, Apr 14, 2017 at 12:15:34PM +0200, Eric Auger wrote:
> This patch adds a new attribute to GICV3 KVM device
> KVM_DEV_ARM_VGIC_GRP_CTRL group. This Allows the userspace to
nit: allows (lowercase)
nit: s/the userspace/userspace/
> flush all GICR pending tables into guest RAM. At the moment
> we do not offer any restore control as the sync is implicit.
I would probably remove the last sentence here.
>
> As we need the PENDBASER_ADDRESS() in vgic-v3, let's move its
> definition in the irqchip header. We restore the full length
> of the field, ie [51:16]. Same for PROPBASER_ADDRESS with full
> field length of [51:12].
>
> Signed-off-by: Eric Auger <eric.auger at redhat.com>
>
> ---
> v4 -> v5:
> - move pending table save code/ctrl into VGICv3 instead of ITS
> - remove useless gpa_t cast
> - use the same optimization as in its_sync_lpi_pending_table
>
> v3 -> v4:
> - remove the wrong comment about locking
> - pass kvm struct instead of its handle
> - add comment about restore method
> - remove GITR_PENDABASER.PTZ check
> - continue if target_vcpu == NULL
> - new locking strategy
>
> v1 -> v2:
> - do not care about the 1st KB which should be zeroed according to
> the spec.
> ---
> arch/arm/include/uapi/asm/kvm.h | 1 +
> arch/arm64/include/uapi/asm/kvm.h | 1 +
> include/linux/irqchip/arm-gic-v3.h | 2 ++
> virt/kvm/arm/vgic/vgic-its.c | 6 ++---
> virt/kvm/arm/vgic/vgic-kvm-device.c | 20 ++++++++++++++
> virt/kvm/arm/vgic/vgic-v3.c | 54 +++++++++++++++++++++++++++++++++++++
> virt/kvm/arm/vgic/vgic.h | 1 +
> 7 files changed, 81 insertions(+), 4 deletions(-)
>
> diff --git a/arch/arm/include/uapi/asm/kvm.h b/arch/arm/include/uapi/asm/kvm.h
> index 8e6563c..78fe803 100644
> --- a/arch/arm/include/uapi/asm/kvm.h
> +++ b/arch/arm/include/uapi/asm/kvm.h
> @@ -202,6 +202,7 @@ struct kvm_arch_memory_slot {
> #define KVM_DEV_ARM_VGIC_CTRL_INIT 0
> #define KVM_DEV_ARM_ITS_SAVE_TABLES 1
> #define KVM_DEV_ARM_ITS_RESTORE_TABLES 2
> +#define KVM_DEV_ARM_VGIC_SAVE_PENDING_TABLES 3
>
> /* KVM_IRQ_LINE irq field index values */
> #define KVM_ARM_IRQ_TYPE_SHIFT 24
> diff --git a/arch/arm64/include/uapi/asm/kvm.h b/arch/arm64/include/uapi/asm/kvm.h
> index 1e35115..8a3758a 100644
> --- a/arch/arm64/include/uapi/asm/kvm.h
> +++ b/arch/arm64/include/uapi/asm/kvm.h
> @@ -222,6 +222,7 @@ struct kvm_arch_memory_slot {
> #define KVM_DEV_ARM_VGIC_CTRL_INIT 0
> #define KVM_DEV_ARM_ITS_SAVE_TABLES 1
> #define KVM_DEV_ARM_ITS_RESTORE_TABLES 2
> +#define KVM_DEV_ARM_VGIC_SAVE_PENDING_TABLES 3
>
> /* Device Control API on vcpu fd */
> #define KVM_ARM_VCPU_PMU_V3_CTRL 0
> diff --git a/include/linux/irqchip/arm-gic-v3.h b/include/linux/irqchip/arm-gic-v3.h
> index 0c6798c..9d3932f 100644
> --- a/include/linux/irqchip/arm-gic-v3.h
> +++ b/include/linux/irqchip/arm-gic-v3.h
> @@ -158,6 +158,7 @@
> #define GICR_PROPBASER_RaWaWb GIC_BASER_CACHEABILITY(GICR_PROPBASER, INNER, RaWaWb)
>
> #define GICR_PROPBASER_IDBITS_MASK (0x1f)
> +#define GICR_PROPBASER_ADDRESS(x) ((x) & GENMASK_ULL(51, 12))
>
> #define GICR_PENDBASER_SHAREABILITY_SHIFT (10)
> #define GICR_PENDBASER_INNER_CACHEABILITY_SHIFT (7)
> @@ -183,6 +184,7 @@
> #define GICR_PENDBASER_RaWaWb GIC_BASER_CACHEABILITY(GICR_PENDBASER, INNER, RaWaWb)
>
> #define GICR_PENDBASER_PTZ BIT_ULL(62)
> +#define GICR_PENDBASER_ADDRESS(x) ((x) & GENMASK_ULL(51, 16))
>
> /*
> * Re-Distributor registers, offsets from SGI_base
> diff --git a/virt/kvm/arm/vgic/vgic-its.c b/virt/kvm/arm/vgic/vgic-its.c
> index be848be..745c245 100644
> --- a/virt/kvm/arm/vgic/vgic-its.c
> +++ b/virt/kvm/arm/vgic/vgic-its.c
> @@ -189,8 +189,6 @@ static struct its_ite *find_ite(struct vgic_its *its, u32 device_id,
> */
> #define BASER_ADDRESS(x) ((x) & GENMASK_ULL(47, 16))
> #define CBASER_ADDRESS(x) ((x) & GENMASK_ULL(47, 12))
> -#define PENDBASER_ADDRESS(x) ((x) & GENMASK_ULL(47, 16))
> -#define PROPBASER_ADDRESS(x) ((x) & GENMASK_ULL(47, 12))
>
> #define GIC_LPI_OFFSET 8192
>
> @@ -227,7 +225,7 @@ static struct its_collection *find_collection(struct vgic_its *its, int coll_id)
> static int update_lpi_config(struct kvm *kvm, struct vgic_irq *irq,
> struct kvm_vcpu *filter_vcpu)
> {
> - u64 propbase = PROPBASER_ADDRESS(kvm->arch.vgic.propbaser);
> + u64 propbase = GICR_PROPBASER_ADDRESS(kvm->arch.vgic.propbaser);
> u8 prop;
> int ret;
>
> @@ -339,7 +337,7 @@ static u32 max_lpis_propbaser(u64 propbaser)
> */
> static int its_sync_lpi_pending_table(struct kvm_vcpu *vcpu)
> {
> - gpa_t pendbase = PENDBASER_ADDRESS(vcpu->arch.vgic_cpu.pendbaser);
> + gpa_t pendbase = GICR_PENDBASER_ADDRESS(vcpu->arch.vgic_cpu.pendbaser);
> struct vgic_irq *irq;
> int last_byte_offset = -1;
> int ret = 0;
> diff --git a/virt/kvm/arm/vgic/vgic-kvm-device.c b/virt/kvm/arm/vgic/vgic-kvm-device.c
> index 859bfa8..d48743c 100644
> --- a/virt/kvm/arm/vgic/vgic-kvm-device.c
> +++ b/virt/kvm/arm/vgic/vgic-kvm-device.c
> @@ -580,6 +580,24 @@ static int vgic_v3_set_attr(struct kvm_device *dev,
> reg = tmp32;
> return vgic_v3_attr_regs_access(dev, attr, ®, true);
> }
> + case KVM_DEV_ARM_VGIC_GRP_CTRL: {
> + int ret;
> +
> + switch (attr->attr) {
> + case KVM_DEV_ARM_VGIC_SAVE_PENDING_TABLES:
> + mutex_lock(&dev->kvm->lock);
> +
> + if (!lock_all_vcpus(dev->kvm)) {
> + mutex_unlock(&dev->kvm->lock);
> + return -EBUSY;
> + }
> + ret = vgic_v3_save_pending_tables(dev->kvm);
> + unlock_all_vcpus(dev->kvm);
> + mutex_unlock(&dev->kvm->lock);
> + return ret;
> + }
> + break;
> + }
> }
> return -ENXIO;
> }
> @@ -658,6 +676,8 @@ static int vgic_v3_has_attr(struct kvm_device *dev,
> switch (attr->attr) {
> case KVM_DEV_ARM_VGIC_CTRL_INIT:
> return 0;
> + case KVM_DEV_ARM_VGIC_SAVE_PENDING_TABLES:
> + return 0;
> }
> }
> return -ENXIO;
> diff --git a/virt/kvm/arm/vgic/vgic-v3.c b/virt/kvm/arm/vgic/vgic-v3.c
> index be0f4c3..1f0977f 100644
> --- a/virt/kvm/arm/vgic/vgic-v3.c
> +++ b/virt/kvm/arm/vgic/vgic-v3.c
> @@ -15,6 +15,7 @@
> #include <linux/irqchip/arm-gic-v3.h>
> #include <linux/kvm.h>
> #include <linux/kvm_host.h>
> +//#include <linux/bitops.h>
> #include <kvm/arm_vgic.h>
> #include <asm/kvm_mmu.h>
> #include <asm/kvm_asm.h>
> @@ -252,6 +253,59 @@ void vgic_v3_enable(struct kvm_vcpu *vcpu)
> vgic_v3->vgic_hcr = ICH_HCR_EN;
> }
>
> +/**
> + * vgic_its_save_pending_tables - Save the pending tables into guest RAM
> + * kvm lock and all vcpu lock must be held
> + */
> +int vgic_v3_save_pending_tables(struct kvm *kvm)
> +{
> + struct vgic_dist *dist = &kvm->arch.vgic;
> + int last_byte_offset = -1;
> + struct vgic_irq *irq;
> + int ret;
> +
> + list_for_each_entry(irq, &dist->lpi_list_head, lpi_list) {
> + int byte_offset, bit_nr;
> + struct kvm_vcpu *vcpu;
> + gpa_t pendbase, ptr;
> + bool stored;
> + u8 val;
> +
> + vcpu = irq->target_vcpu;
> + if (!vcpu)
> + continue;
> +
> + pendbase = GICR_PENDBASER_ADDRESS(vcpu->arch.vgic_cpu.pendbaser);
> +
> + byte_offset = irq->intid / BITS_PER_BYTE;
> + bit_nr = irq->intid % BITS_PER_BYTE;
> + ptr = pendbase + byte_offset;
> +
> + if (byte_offset != last_byte_offset) {
> + ret = kvm_read_guest(kvm, ptr, &val, 1);
> + if (ret)
> + return ret;
> + last_byte_offset = byte_offset;
> + }
> +
> + stored = val & bit_nr;
didn't you mean 'stored = val & (1 << bit_nr)' ?
> + if (stored == irq->pending_latch)
> + continue;
> +
> + if (irq->pending_latch)
> + val |= 1 << bit_nr;
> + else
> + val &= ~(1 << bit_nr);
> +
> + ret = kvm_write_guest(kvm, ptr, &val, 1);
> + if (ret)
> + return ret;
> + }
This loop could probably be written a bit more efficiently and
simplicity by reading the memory one word at a time (and remembering to
do le64_to_cpu) and then doing something like:
if (irq->pending_latch)
old = __test_and_set_bit(bit_nr, &val);
else
old = __test_and_clear_bit(bit_nr, &val);
if (old != val) {
tmp = cpu_to_le64(val);
ret = kvm_write_guest(kvm, ptr, &tmp,
sizeof(unsigned long));
if (ret)
retur ret;
}
Further, you could also detect when the word_offset changes and write
back the entire word with all its changes then, but you'd also have to
check at the end of the loop then. Not sure that's worth the
optimization or easier to read than what you heave. It's up to you.
Thanks,
-Christoffer
> +
> + return 0;
> +}
> +
> +
> /* check for overlapping regions and for regions crossing the end of memory */
> static bool vgic_v3_check_base(struct kvm *kvm)
> {
> diff --git a/virt/kvm/arm/vgic/vgic.h b/virt/kvm/arm/vgic/vgic.h
> index 9bc52ef..535c2fc 100644
> --- a/virt/kvm/arm/vgic/vgic.h
> +++ b/virt/kvm/arm/vgic/vgic.h
> @@ -177,6 +177,7 @@ void vgic_v3_get_vmcr(struct kvm_vcpu *vcpu, struct vgic_vmcr *vmcr);
> void vgic_v3_enable(struct kvm_vcpu *vcpu);
> int vgic_v3_probe(const struct gic_kvm_info *info);
> int vgic_v3_map_resources(struct kvm *kvm);
> +int vgic_v3_save_pending_tables(struct kvm *kvm);
> int vgic_register_redist_iodevs(struct kvm *kvm, gpa_t dist_base_address);
>
> int vgic_register_its_iodevs(struct kvm *kvm);
> --
> 2.5.5
>
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