[RFC PATCH 15/16] KVM: arm64: Enumerate SVE register indices for KVM_GET_REG_LIST

Dave Martin
2018-06-21T14:47:38Z

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 extra IDs are added.

On an SVE-enabled vcpu, the appropriate number of slide IDs are
enumerated for each SVE register, depending on the maximum vector
length for the vcpu.

Signed-off-by: Dave Martin <Dave.Martin@arm.com>
---
arch/arm64/kvm/guest.c | 73 ++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 73 insertions(+)

diff --git a/arch/arm64/kvm/guest.c b/arch/arm64/kvm/guest.c
index 005394b..5152362 100644
--- a/arch/arm64/kvm/guest.c
+++ b/arch/arm64/kvm/guest.c
@@ -21,6 +21,7 @@

#include <linux/errno.h>
#include <linux/err.h>
+#include <linux/kernel.h>
#include <linux/kvm_host.h>
#include <linux/module.h>
#include <linux/uaccess.h>
@@ -253,6 +254,73 @@ static int set_core_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
return err;
}

+static void copy_reg_index_to_user(u64 __user **uind, int *total, int *cerr,
+ u64 id)
+{
+ int err;
+
+ if (*cerr)
+ return;
+
+ if (uind) {
+ err = put_user(id, *uind);
+ if (err) {
+ *cerr = err;
+ return;
+ }
+ }
+
+ ++*total;
+ if (uind)
+ ++*uind;
+}
+
+static int enumerate_sve_regs(const struct kvm_vcpu *vcpu, u64 __user **uind)
+{
+ unsigned int n, i;
+ int err = 0;
+ int total = 0;
+ unsigned int slices;
+
+ if (!vcpu_has_sve(&vcpu->arch))
+ return 0;
+
+ slices = DIV_ROUND_UP(vcpu->arch.sve_max_vl,
+ KVM_REG_SIZE(KVM_REG_ARM64_SVE_ZREG(0, 0)));
+
+ for (n = 0; n < SVE_NUM_ZREGS; ++n)
+ for (i = 0; i < slices; ++i)
+ copy_reg_index_to_user(uind, &total, &err,
+ KVM_REG_ARM64_SVE_ZREG(n, i));
+
+ for (n = 0; n < SVE_NUM_PREGS; ++n)
+ for (i = 0; i < slices; ++i)
+ copy_reg_index_to_user(uind, &total, &err,
+ KVM_REG_ARM64_SVE_PREG(n, i));
+
+ for (i = 0; i < slices; ++i)
+ copy_reg_index_to_user(uind, &total, &err,
+ KVM_REG_ARM64_SVE_FFR(i));
+
+ if (err)
+ return -EFAULT;
+
+ return total;
+}
+
+static unsigned long num_sve_regs(const struct kvm_vcpu *vcpu)
+{
+ return enumerate_sve_regs(vcpu, NULL);
+}
+
+static int copy_sve_reg_indices(const struct kvm_vcpu *vcpu, u64 __user **uind)
+{
+ int err;
+
+ err = enumerate_sve_regs(vcpu, uind);
+ return err < 0 ? err : 0;
+}
+
static int sve_reg_bounds(struct reg_bounds_struct *b,
const struct kvm_vcpu *vcpu,
const struct kvm_one_reg *reg)
@@ -403,6 +471,7 @@ unsigned long kvm_arm_num_regs(struct kvm_vcpu *vcpu)
unsigned long res = 0;

res += num_core_regs();
+ 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;
@@ -427,6 +496,10 @@ int kvm_arm_copy_reg_indices(struct kvm_vcpu *vcpu, u64 __user *uindices)
uindices++;
}

+ 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