[PATCH v4 05/13] ARM: KVM: VGIC accept vcpu and dist base addresses from user space
Christoffer Dall
c.dall at virtualopensystems.com
Sat Dec 1 10:57:41 EST 2012
On Fri, Nov 30, 2012 at 9:52 PM, Christoffer Dall
<c.dall at virtualopensystems.com> wrote:
> On Wed, Nov 28, 2012 at 8:11 AM, Will Deacon <will.deacon at arm.com> wrote:
>> On Sat, Nov 10, 2012 at 03:44:51PM +0000, Christoffer Dall wrote:
>>> User space defines the model to emulate to a guest and should therefore
>>> decide which addresses are used for both the virtual CPU interface
>>> directly mapped in the guest physical address space and for the emulated
>>> distributor interface, which is mapped in software by the in-kernel VGIC
>>> support.
>>>
>>> Signed-off-by: Christoffer Dall <c.dall at virtualopensystems.com>
>>> ---
>>> arch/arm/include/asm/kvm_mmu.h | 2 +
>>> arch/arm/include/asm/kvm_vgic.h | 9 ++++++
>>> arch/arm/kvm/arm.c | 16 ++++++++++
>>> arch/arm/kvm/vgic.c | 61 +++++++++++++++++++++++++++++++++++++++
>>> 4 files changed, 87 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/arch/arm/include/asm/kvm_mmu.h b/arch/arm/include/asm/kvm_mmu.h
>>> index 9bd0508..0800531 100644
>>> --- a/arch/arm/include/asm/kvm_mmu.h
>>> +++ b/arch/arm/include/asm/kvm_mmu.h
>>> @@ -26,6 +26,8 @@
>>> * To save a bit of memory and to avoid alignment issues we assume 39-bit IPA
>>> * for now, but remember that the level-1 table must be aligned to its size.
>>> */
>>> +#define KVM_PHYS_SHIFT (38)
>>
>> Seems a bit small...
>>
>>> +#define KVM_PHYS_MASK ((1ULL << KVM_PHYS_SHIFT) - 1)
>>> #define PTRS_PER_PGD2 512
>>> #define PGD2_ORDER get_order(PTRS_PER_PGD2 * sizeof(pgd_t))
>>>
>>> diff --git a/arch/arm/include/asm/kvm_vgic.h b/arch/arm/include/asm/kvm_vgic.h
>>> index b444ecf..9ca8d21 100644
>>> --- a/arch/arm/include/asm/kvm_vgic.h
>>> +++ b/arch/arm/include/asm/kvm_vgic.h
>>> @@ -20,6 +20,9 @@
>>> #define __ASM_ARM_KVM_VGIC_H
>>>
>>> struct vgic_dist {
>>> + /* Distributor and vcpu interface mapping in the guest */
>>> + phys_addr_t vgic_dist_base;
>>> + phys_addr_t vgic_cpu_base;
>>> };
>>>
>>> struct vgic_cpu {
>>> @@ -31,6 +34,7 @@ struct kvm_run;
>>> struct kvm_exit_mmio;
>>>
>>> #ifdef CONFIG_KVM_ARM_VGIC
>>> +int kvm_vgic_set_addr(struct kvm *kvm, unsigned long type, u64 addr);
>>> bool vgic_handle_mmio(struct kvm_vcpu *vcpu, struct kvm_run *run,
>>> struct kvm_exit_mmio *mmio);
>>>
>>> @@ -40,6 +44,11 @@ static inline int kvm_vgic_hyp_init(void)
>>> return 0;
>>> }
>>>
>>> +static inline int kvm_vgic_set_addr(struct kvm *kvm, unsigned long type, u64 addr)
>>> +{
>>> + return 0;
>>> +}
>>> +
>>> static inline int kvm_vgic_init(struct kvm *kvm)
>>> {
>>> return 0;
>>> diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c
>>> index 426828a..3ac1aab 100644
>>> --- a/arch/arm/kvm/arm.c
>>> +++ b/arch/arm/kvm/arm.c
>>> @@ -61,6 +61,8 @@ static atomic64_t kvm_vmid_gen = ATOMIC64_INIT(1);
>>> static u8 kvm_next_vmid;
>>> static DEFINE_SPINLOCK(kvm_vmid_lock);
>>>
>>> +static bool vgic_present;
>>> +
>>> static void kvm_arm_set_running_vcpu(struct kvm_vcpu *vcpu)
>>> {
>>> BUG_ON(preemptible());
>>> @@ -825,7 +827,19 @@ int kvm_vm_ioctl_get_dirty_log(struct kvm *kvm, struct kvm_dirty_log *log)
>>> static int kvm_vm_ioctl_set_device_address(struct kvm *kvm,
>>> struct kvm_device_address *dev_addr)
>>> {
>>> - return -ENODEV;
>>> + unsigned long dev_id, type;
>>> +
>>> + dev_id = (dev_addr->id & KVM_DEVICE_ID_MASK) >> KVM_DEVICE_ID_SHIFT;
>>> + type = (dev_addr->id & KVM_DEVICE_TYPE_MASK) >> KVM_DEVICE_TYPE_SHIFT;
>>> +
>>> + switch (dev_id) {
>>> + case KVM_ARM_DEVICE_VGIC_V2:
>>> + if (!vgic_present)
>>> + return -ENXIO;
>>> + return kvm_vgic_set_addr(kvm, type, dev_addr->addr);
>>> + default:
>>> + return -ENODEV;
>>> + }
>>> }
>>>
>>> long kvm_arch_vm_ioctl(struct file *filp,
>>> diff --git a/arch/arm/kvm/vgic.c b/arch/arm/kvm/vgic.c
>>> index 26ada3b..f85b275 100644
>>> --- a/arch/arm/kvm/vgic.c
>>> +++ b/arch/arm/kvm/vgic.c
>>> @@ -22,6 +22,13 @@
>>> #include <linux/io.h>
>>> #include <asm/kvm_emulate.h>
>>>
>>> +#define VGIC_ADDR_UNDEF (-1)
>>> +#define IS_VGIC_ADDR_UNDEF(_x) ((_x) == (typeof(_x))VGIC_ADDR_UNDEF)
>>> +
>>> +#define VGIC_DIST_SIZE 0x1000
>>> +#define VGIC_CPU_SIZE 0x2000
>>
>> These defines might be useful to userspace so that they don't request the
>> distributor and the cpu interface to be place too close together (been there,
>> done that :).
>>
>>> +
>>> +
>>> #define ACCESS_READ_VALUE (1 << 0)
>>> #define ACCESS_READ_RAZ (0 << 0)
>>> #define ACCESS_READ_MASK(x) ((x) & (1 << 0))
>>> @@ -136,3 +143,57 @@ bool vgic_handle_mmio(struct kvm_vcpu *vcpu, struct kvm_run *run, struct kvm_exi
>>> {
>>> return KVM_EXIT_MMIO;
>>> }
>>> +
>>> +static bool vgic_ioaddr_overlap(struct kvm *kvm)
>>> +{
>>> + phys_addr_t dist = kvm->arch.vgic.vgic_dist_base;
>>> + phys_addr_t cpu = kvm->arch.vgic.vgic_cpu_base;
>>> +
>>> + if (IS_VGIC_ADDR_UNDEF(dist) || IS_VGIC_ADDR_UNDEF(cpu))
>>> + return false;
>>> + if ((dist <= cpu && dist + VGIC_DIST_SIZE > cpu) ||
>>> + (cpu <= dist && cpu + VGIC_CPU_SIZE > dist))
>>> + return true;
>>> + return false;
>>
>> Just return the predicate that you're testing.
>>
>>> +}
>>> +
>>> +int kvm_vgic_set_addr(struct kvm *kvm, unsigned long type, u64 addr)
>>> +{
>>> + int r = 0;
>>> + struct vgic_dist *vgic = &kvm->arch.vgic;
>>> +
>>> + if (addr & ~KVM_PHYS_MASK)
>>> + return -E2BIG;
>>> +
>>> + if (addr & ~PAGE_MASK)
>>> + return -EINVAL;
>>> +
>>> + mutex_lock(&kvm->lock);
>>> + switch (type) {
>>> + case KVM_VGIC_V2_ADDR_TYPE_DIST:
>>> + if (!IS_VGIC_ADDR_UNDEF(vgic->vgic_dist_base))
>>> + return -EEXIST;
>>> + if (addr + VGIC_DIST_SIZE < addr)
>>> + return -EINVAL;
>>
>> I think somebody else pointed out the missing mutex_unlocks on the failure
>> paths.
>>
>>> + kvm->arch.vgic.vgic_dist_base = addr;
>>> + break;
>>> + case KVM_VGIC_V2_ADDR_TYPE_CPU:
>>> + if (!IS_VGIC_ADDR_UNDEF(vgic->vgic_cpu_base))
>>> + return -EEXIST;
>>> + if (addr + VGIC_CPU_SIZE < addr)
>>> + return -EINVAL;
>>> + kvm->arch.vgic.vgic_cpu_base = addr;
>>> + break;
>>> + default:
>>> + r = -ENODEV;
>>> + }
>>> +
>>> + if (vgic_ioaddr_overlap(kvm)) {
>>> + kvm->arch.vgic.vgic_dist_base = VGIC_ADDR_UNDEF;
>>> + kvm->arch.vgic.vgic_cpu_base = VGIC_ADDR_UNDEF;
>>> + return -EINVAL;
>>
>> Perhaps we could put all the address checking in one place, so that the wrapping
>> round zero checks and the overlap checks can be in the same function?
>>
>
> Like this (?):
>
and by this, I mean this:
diff --git a/Documentation/virtual/kvm/api.txt
b/Documentation/virtual/kvm/api.txt
index 7f057a2..0b6b95e 100644
--- a/Documentation/virtual/kvm/api.txt
+++ b/Documentation/virtual/kvm/api.txt
@@ -2163,6 +2163,7 @@ Errors:
ENXIO: Device not supported on current system
EEXIST: Address already set
E2BIG: Address outside guest physical address space
+ EBUSY: Address overlaps with other device range
struct kvm_device_address {
__u64 id;
diff --git a/arch/arm/kvm/vgic.c b/arch/arm/kvm/vgic.c
index f697c14..c666b95 100644
--- a/arch/arm/kvm/vgic.c
+++ b/arch/arm/kvm/vgic.c
@@ -1230,11 +1230,28 @@ static bool vgic_ioaddr_overlap(struct kvm *kvm)
phys_addr_t cpu = kvm->arch.vgic.vgic_cpu_base;
if (IS_VGIC_ADDR_UNDEF(dist) || IS_VGIC_ADDR_UNDEF(cpu))
- return false;
+ return 0;
if ((dist <= cpu && dist + VGIC_DIST_SIZE > cpu) ||
(cpu <= dist && cpu + VGIC_CPU_SIZE > dist))
- return true;
- return false;
+ return -EBUSY;
+ return 0;
+}
+
+static int vgic_ioaddr_assign(struct kvm *kvm, phys_addr_t *ioaddr,
+ phys_addr_t addr, phys_addr_t size)
+{
+ int ret;
+
+ if (!IS_VGIC_ADDR_UNDEF(*ioaddr))
+ return -EEXIST;
+ if (addr + size < addr)
+ return -EINVAL;
+
+ ret = vgic_ioaddr_overlap(kvm);
+ if (ret)
+ return ret;
+ *ioaddr = addr;
+ return ret;
}
int kvm_vgic_set_addr(struct kvm *kvm, unsigned long type, u64 addr)
@@ -1251,29 +1268,17 @@ int kvm_vgic_set_addr(struct kvm *kvm,
unsigned long type, u64 addr)
mutex_lock(&kvm->lock);
switch (type) {
case KVM_VGIC_V2_ADDR_TYPE_DIST:
- if (!IS_VGIC_ADDR_UNDEF(vgic->vgic_dist_base))
- return -EEXIST;
- if (addr + VGIC_DIST_SIZE < addr)
- return -EINVAL;
- kvm->arch.vgic.vgic_dist_base = addr;
+ r = vgic_ioaddr_assign(kvm, &vgic->vgic_dist_base,
+ addr, VGIC_DIST_SIZE);
break;
case KVM_VGIC_V2_ADDR_TYPE_CPU:
- if (!IS_VGIC_ADDR_UNDEF(vgic->vgic_cpu_base))
- return -EEXIST;
- if (addr + VGIC_CPU_SIZE < addr)
- return -EINVAL;
- kvm->arch.vgic.vgic_cpu_base = addr;
+ r = vgic_ioaddr_assign(kvm, &vgic->vgic_cpu_base,
+ addr, VGIC_CPU_SIZE);
break;
default:
r = -ENODEV;
}
- if (vgic_ioaddr_overlap(kvm)) {
- kvm->arch.vgic.vgic_dist_base = VGIC_ADDR_UNDEF;
- kvm->arch.vgic.vgic_cpu_base = VGIC_ADDR_UNDEF;
- r = -EINVAL;
- }
-
mutex_unlock(&kvm->lock);
return r;
}
--
Thanks,
-Christoffer
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