KVM: arm64: Introduce generic get_user/set_user helpers for system registers

The userspace access to the system registers is done using helpers
that hardcode the table that is looked up. extract some generic
helpers from this, moving the handling of hidden sysregs into
the core code.

Reviewed-by: Reiji Watanabe <reijiw@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>

diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index 9291cb94c2e4531c46982d2a10158c8f6d14a661..0fbdb21a36002d1d29e823c911ecdfe198c14d14 100644 (file)
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -2663,8 +2663,10 @@ const struct sys_reg_desc *get_reg_by_id(u64 id,
 }
 
 /* Decode an index value, and find the sys_reg_desc entry. */
-static const struct sys_reg_desc *index_to_sys_reg_desc(struct kvm_vcpu *vcpu,
-                                                   u64 id)
+static const struct sys_reg_desc *
+id_to_sys_reg_desc(struct kvm_vcpu *vcpu, u64 id,
+                  const struct sys_reg_desc table[], unsigned int num)
+
 {
        const struct sys_reg_desc *r;
 
@@ -2672,10 +2674,10 @@ static const struct sys_reg_desc *index_to_sys_reg_desc(struct kvm_vcpu *vcpu,
        if ((id & KVM_REG_ARM_COPROC_MASK) != KVM_REG_ARM64_SYSREG)
                return NULL;
 
-       r = get_reg_by_id(id, sys_reg_descs, ARRAY_SIZE(sys_reg_descs));
+       r = get_reg_by_id(id, table, num);
 
        /* Not saved in the sys_reg array and not otherwise accessible? */
-       if (r && !(r->reg || r->get_user))
+       if (r && (!(r->reg || r->get_user) || sysreg_hidden(vcpu, r)))
                r = NULL;
 
        return r;
@@ -2845,9 +2847,24 @@ static int demux_c15_set(u64 id, void __user *uaddr)
        }
 }
 
-int kvm_arm_sys_reg_get_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
+int kvm_sys_reg_get_user(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg,
+                        const struct sys_reg_desc table[], unsigned int num)
 {
+       void __user *uaddr = (void __user *)(unsigned long)reg->addr;
        const struct sys_reg_desc *r;
+
+       r = id_to_sys_reg_desc(vcpu, reg->id, table, num);
+       if (!r)
+               return -ENOENT;
+
+       if (r->get_user)
+               return (r->get_user)(vcpu, r, reg, uaddr);
+
+       return reg_to_user(uaddr, &__vcpu_sys_reg(vcpu, r->reg), reg->id);
+}
+
+int kvm_arm_sys_reg_get_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
+{
        void __user *uaddr = (void __user *)(unsigned long)reg->addr;
        int err;
 
@@ -2861,21 +2878,28 @@ int kvm_arm_sys_reg_get_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg
        if (err != -ENOENT)
                return err;
 
-       r = index_to_sys_reg_desc(vcpu, reg->id);
+       return kvm_sys_reg_get_user(vcpu, reg,
+                                   sys_reg_descs, ARRAY_SIZE(sys_reg_descs));
+}
 
-       /* Check for regs disabled by runtime config */
-       if (!r || sysreg_hidden(vcpu, r))
+int kvm_sys_reg_set_user(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg,
+                        const struct sys_reg_desc table[], unsigned int num)
+{
+       void __user *uaddr = (void __user *)(unsigned long)reg->addr;
+       const struct sys_reg_desc *r;
+
+       r = id_to_sys_reg_desc(vcpu, reg->id, table, num);
+       if (!r)
                return -ENOENT;
 
-       if (r->get_user)
-               return (r->get_user)(vcpu, r, reg, uaddr);
+       if (r->set_user)
+               return (r->set_user)(vcpu, r, reg, uaddr);
 
-       return reg_to_user(uaddr, &__vcpu_sys_reg(vcpu, r->reg), reg->id);
+       return reg_from_user(&__vcpu_sys_reg(vcpu, r->reg), uaddr, reg->id);
 }
 
 int kvm_arm_sys_reg_set_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
 {
-       const struct sys_reg_desc *r;
        void __user *uaddr = (void __user *)(unsigned long)reg->addr;
        int err;
 
@@ -2889,16 +2913,8 @@ int kvm_arm_sys_reg_set_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg
        if (err != -ENOENT)
                return err;
 
-       r = index_to_sys_reg_desc(vcpu, reg->id);
-
-       /* Check for regs disabled by runtime config */
-       if (!r || sysreg_hidden(vcpu, r))
-               return -ENOENT;
-
-       if (r->set_user)
-               return (r->set_user)(vcpu, r, reg, uaddr);
-
-       return reg_from_user(&__vcpu_sys_reg(vcpu, r->reg), uaddr, reg->id);
+       return kvm_sys_reg_set_user(vcpu, reg,
+                                   sys_reg_descs, ARRAY_SIZE(sys_reg_descs));
 }
 
 static unsigned int num_demux_regs(void)

diff --git a/arch/arm64/kvm/sys_regs.h b/arch/arm64/kvm/sys_regs.h
index ce30ed9566ae0a1d103137de2b74e71a71b304fb..4fb6d59e78747b7f8693d2854ecc894e0c7c9fd2 100644 (file)
--- a/arch/arm64/kvm/sys_regs.h
+++ b/arch/arm64/kvm/sys_regs.h
@@ -199,6 +199,12 @@ const struct sys_reg_desc *get_reg_by_id(u64 id,
                                         const struct sys_reg_desc table[],
                                         unsigned int num);
 
+int kvm_sys_reg_get_user(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg,
+                        const struct sys_reg_desc table[], unsigned int num);
+
+int kvm_sys_reg_set_user(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg,
+                        const struct sys_reg_desc table[], unsigned int num);
+
 #define AA32(_x)       .aarch32_map = AA32_##_x
 #define Op0(_x)        .Op0 = _x
 #define Op1(_x)        .Op1 = _x