In order to avoid the pointless complexity of maintaining two ioctl
register access views of the same data, this patch blocks ioctl
access to the FPSIMD V-registers on vcpus that support SVE.
This will make it more straightforward to add SVE register access
support.
Since SVE is an opt-in feature for userspace, this will not affect
existing users.
Signed-off-by: Dave Martin <dave.mar...@arm.com>
---
arch/arm64/kvm/guest.c | 38 +++++++++++++++++++++++++++-----------
1 file changed, 27 insertions(+), 11 deletions(-)
diff --git a/arch/arm64/kvm/guest.c b/arch/arm64/kvm/guest.c
index f83fe22..f491456 100644
--- a/arch/arm64/kvm/guest.c
+++ b/arch/arm64/kvm/guest.c
@@ -95,7 +95,14 @@ static int core_reg_size_from_offset(u64 off)
return -EINVAL;
}
-static int validate_core_offset(const struct kvm_one_reg *reg)
+static bool core_reg_offset_is_vreg(u64 off)
+{
+ return off >= KVM_REG_ARM_CORE_REG(fp_regs.vregs) &&
+ off < KVM_REG_ARM_CORE_REG(fp_regs.fpsr);
+}
+
+static int validate_core_offset(const struct kvm_vcpu *vcpu,
+ const struct kvm_one_reg *reg)
{
u64 off = core_reg_offset_from_id(reg->id);
int size = core_reg_size_from_offset(off);
@@ -103,10 +110,18 @@ static int validate_core_offset(const struct kvm_one_reg
*reg)
if (size < 0)
return -EINVAL;
- if (KVM_REG_SIZE(reg->id) == size)
- return 0;
+ if (KVM_REG_SIZE(reg->id) != size)
+ return -EINVAL;
- return -EINVAL;
+ /*
+ * The KVM_REG_ARM64_SVE regs must be used instead of
+ * KVM_REG_ARM_CORE for accessing the FPSIMD V-registers on
+ * SVE-enabled vcpus:
+ */
+ if (vcpu_has_sve(vcpu) && core_reg_offset_is_vreg(off))
+ return -EINVAL;
+
+ return 0;
}
static int get_core_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
@@ -128,7 +143,7 @@ static int get_core_reg(struct kvm_vcpu *vcpu, const struct
kvm_one_reg *reg)
(off + (KVM_REG_SIZE(reg->id) / sizeof(__u32))) >= nr_regs)
return -ENOENT;
- if (validate_core_offset(reg))
+ if (validate_core_offset(vcpu, reg))
return -EINVAL;
if (copy_to_user(uaddr, ((u32 *)regs) + off, KVM_REG_SIZE(reg->id)))
@@ -153,7 +168,7 @@ static int set_core_reg(struct kvm_vcpu *vcpu, const struct
kvm_one_reg *reg)
(off + (KVM_REG_SIZE(reg->id) / sizeof(__u32))) >= nr_regs)
return -ENOENT;
- if (validate_core_offset(reg))
+ if (validate_core_offset(vcpu, reg))
return -EINVAL;
if (KVM_REG_SIZE(reg->id) > sizeof(tmp))
@@ -206,7 +221,8 @@ int kvm_arch_vcpu_ioctl_set_regs(struct kvm_vcpu *vcpu,
struct kvm_regs *regs)
return -EINVAL;
}
-static int copy_core_reg_indices(u64 __user **uind)
+static int copy_core_reg_indices(const struct kvm_vcpu *vcpu,
+ u64 __user **uind)
{
unsigned int i;
int n = 0;
@@ -248,9 +264,9 @@ static int copy_core_reg_indices(u64 __user **uind)
return n;
}
-static unsigned long num_core_regs(void)
+static unsigned long num_core_regs(const struct kvm_vcpu *vcpu)
{
- return copy_core_reg_indices(NULL);
+ return copy_core_reg_indices(vcpu, NULL);
}
/**
@@ -315,7 +331,7 @@ unsigned long kvm_arm_num_regs(struct kvm_vcpu *vcpu)
{
unsigned long res = 0;
- res += num_core_regs();
+ res += num_core_regs(vcpu);
res += kvm_arm_num_sys_reg_descs(vcpu);
res += kvm_arm_get_fw_num_regs(vcpu);
res += NUM_TIMER_REGS;
@@ -332,7 +348,7 @@ int kvm_arm_copy_reg_indices(struct kvm_vcpu *vcpu, u64
__user *uindices)
{
int ret;
- ret = copy_core_reg_indices(&uindices);
+ ret = copy_core_reg_indices(vcpu, &uindices);
if (ret < 0)
return ret;
--
2.1.4
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