This patch includes the SVE register IDs in the list returned by
KVM_GET_REG_LIST, as appropriate.
On a non-SVE-enabled vcpu, no new IDs are added.
On an SVE-enabled vcpu, IDs for the FPSIMD V-registers are removed
from the list, since userspace is required to access the Z-
registers instead to access their context. For the variably-
sized SVE registers, the appropriate set of slice IDs are
enumerated, depending on the maximum vector length for the vcpu.
Signed-off-by: Dave Martin <Dave.Martin@xxxxxxx>
---
Changes since RFC v3:
* Don't enumerate FPSIMD V-regs for SVE vcpus.
---
arch/arm64/kvm/guest.c | 60 ++++++++++++++++++++++++++++++++++++++++++++++++--
1 file changed, 58 insertions(+), 2 deletions(-)
diff --git a/arch/arm64/kvm/guest.c b/arch/arm64/kvm/guest.c
index b8f9c1e..2d248e7 100644
--- a/arch/arm64/kvm/guest.c
+++ b/arch/arm64/kvm/guest.c
@@ -234,6 +234,11 @@ struct kreg_region {
#define SVE_NUM_SLICES (1 << SVE_REG_SLICE_BITS)
+#define KVM_SVE_ZREG_SIZE KVM_REG_SIZE(KVM_REG_ARM64_SVE_ZREG(0, 0))
+#define KVM_SVE_PREG_SIZE KVM_REG_SIZE(KVM_REG_ARM64_SVE_PREG(0, 0))
+#define KVM_SVE_SLICES(vcpu) \
+ DIV_ROUND_UP((vcpu)->arch.sve_max_vl, KVM_SVE_ZREG_SIZE)
+
static int sve_reg_region(struct kreg_region *b,
const struct kvm_vcpu *vcpu,
const struct kvm_one_reg *reg)
@@ -251,7 +256,7 @@ static int sve_reg_region(struct kreg_region *b,
if (reg->id >= KVM_REG_ARM64_SVE_ZREG(0, 0) &&
reg->id <= KVM_REG_ARM64_SVE_ZREG(SVE_NUM_ZREGS - 1,
SVE_NUM_SLICES - 1)) {
- slice_size = KVM_REG_SIZE(KVM_REG_ARM64_SVE_ZREG(0, 0));
+ slice_size = KVM_SVE_ZREG_SIZE;
/* Compute start and end of the register: */
offset = SVE_SIG_ZREG_OFFSET(vq, reg_num) - SVE_SIG_REGS_OFFSET;
@@ -263,7 +268,7 @@ static int sve_reg_region(struct kreg_region *b,
reg->id <= KVM_REG_ARM64_SVE_FFR(SVE_NUM_SLICES - 1)) {
/* (FFR is P16 for our purposes) */
- slice_size = KVM_REG_SIZE(KVM_REG_ARM64_SVE_PREG(0, 0));
+ slice_size = KVM_SVE_PREG_SIZE;
/* Compute start and end of the register: */
offset = SVE_SIG_PREG_OFFSET(vq, reg_num) - SVE_SIG_REGS_OFFSET;
@@ -358,6 +363,14 @@ static int copy_core_reg_indices(const struct kvm_vcpu *vcpu,
continue;
}
+ /*
+ * 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(i))
+ continue;
+
if (uind) {
if (put_user(reg, *uind))
return -EFAULT;
@@ -428,6 +441,44 @@ static int get_timer_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
return copy_to_user(uaddr, &val, KVM_REG_SIZE(reg->id)) ? -EFAULT : 0;
}
+static unsigned long num_sve_regs(const struct kvm_vcpu *vcpu)
+{
+ unsigned int slices;
+
+ if (!vcpu_has_sve(vcpu))
+ return 0;
+
+ slices = KVM_SVE_SLICES(vcpu);
+ return slices * (SVE_NUM_PREGS + SVE_NUM_ZREGS + 1 /* FFR */);
+}
+
+static int copy_sve_reg_indices(const struct kvm_vcpu *vcpu, u64 __user **uind)
+{
+ unsigned int slices, i, n;
+
+ if (!vcpu_has_sve(vcpu))
+ return 0;
+
+ slices = KVM_SVE_SLICES(vcpu);
+
+ for (i = 0; i < slices; i++) {
+ for (n = 0; n < SVE_NUM_ZREGS; n++) {
+ if (put_user(KVM_REG_ARM64_SVE_ZREG(n, i), (*uind)++))
+ return -EFAULT;
+ }
+
+ for (n = 0; n < SVE_NUM_PREGS; n++) {
+ if (put_user(KVM_REG_ARM64_SVE_PREG(n, i), (*uind)++))
+ return -EFAULT;
+ }
+
+ if (put_user(KVM_REG_ARM64_SVE_FFR(i), (*uind)++))
+ return -EFAULT;
+ }
+
+ return 0;
+}
+
/**
* kvm_arm_num_regs - how many registers do we present via KVM_GET_ONE_REG
*
@@ -438,6 +489,7 @@ unsigned long kvm_arm_num_regs(struct kvm_vcpu *vcpu)
unsigned long res = 0;
res += num_core_regs(vcpu);
+ res += num_sve_regs(vcpu);
res += kvm_arm_num_sys_reg_descs(vcpu);
res += kvm_arm_get_fw_num_regs(vcpu);
res += NUM_TIMER_REGS;
@@ -458,6 +510,10 @@ int kvm_arm_copy_reg_indices(struct kvm_vcpu *vcpu, u64 __user *uindices)
if (ret < 0)
return ret;
+ ret = copy_sve_reg_indices(vcpu, &uindices);
+ if (ret)
+ return ret;
+
ret = kvm_arm_copy_fw_reg_indices(vcpu, uindices);
if (ret)
return ret;
--
2.1.4
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