diff mbox series

[03/19] KVM: arm64: Introduce generic get_user/set_user helpers for system registers

Message ID 20220706164304.1582687-4-maz@kernel.org (mailing list archive)
State New, archived
Headers show
Series KVM: arm64: vgic-v3 userspace access consolidation (and other goodies) | expand

Commit Message

Marc Zyngier July 6, 2022, 4:42 p.m. UTC 
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.

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 arch/arm64/kvm/sys_regs.c | 60 +++++++++++++++++++++++++--------------
 arch/arm64/kvm/sys_regs.h |  6 ++++
 2 files changed, 44 insertions(+), 22 deletions(-)

Comments

Oliver Upton July 8, 2022, 7:20 p.m. UTC | #1 
On Wed, Jul 06, 2022 at 05:42:48PM +0100, Marc Zyngier wrote:
> 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.
> 
> Signed-off-by: Marc Zyngier <maz@kernel.org>

Reviewed-by: Oliver Upton <oliver.upton@linux.dev>
Reiji Watanabe July 9, 2022, 6:59 a.m. UTC | #2 
On Wed, Jul 6, 2022 at 9:43 AM Marc Zyngier <maz@kernel.org> wrote:
>
> 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.
>
> Signed-off-by: Marc Zyngier <maz@kernel.org>

Reviewed-by: Reiji Watanabe <reijiw@google.com>
diff mbox series

Patch

diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index 9291cb94c2e4..0fbdb21a3600 100644
--- 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 ce30ed9566ae..4fb6d59e7874 100644
--- 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