[PATCH 5/5] KVM: arm64: Remove AA64ZFR0_EL1 accessors

Marc Zyngier
2020-11-06T16:44:43Z

The AA64ZFR0_EL1 accessors are just the general accessors with
its visibility function open-coded. It also skips the if-else
chain in read_id_reg, but there's no reason not to go there.
Indeed consolidating ID register accessors and removing lines
of code make it worthwhile.

Remove the AA64ZFR0_EL1 accessors, replacing them with the
general accessors for sanitized ID registers.

No functional change intended.

Signed-off-by: Andrew Jones <drjones@redhat.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20201105091022.15373-5-drjones@redhat.com
---
arch/arm64/kvm/sys_regs.c | 61 +++++++--------------------------------
1 file changed, 11 insertions(+), 50 deletions(-)

diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index 4ee098abd87c..436043cd327e 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -1154,6 +1154,16 @@ static u64 read_id_reg(const struct kvm_vcpu *vcpu,
static unsigned int id_visibility(const struct kvm_vcpu *vcpu,
const struct sys_reg_desc *r)
{
+ u32 id = sys_reg((u32)r->Op0, (u32)r->Op1,
+ (u32)r->CRn, (u32)r->CRm, (u32)r->Op2);
+
+ switch (id) {
+ case SYS_ID_AA64ZFR0_EL1:
+ if (!vcpu_has_sve(vcpu))
+ return REG_RAZ;
+ break;
+ }
+
return 0;
}

@@ -1201,55 +1211,6 @@ static unsigned int sve_visibility(const struct kvm_vcpu *vcpu,
return REG_HIDDEN;
}

-/* Generate the emulated ID_AA64ZFR0_EL1 value exposed to the guest */
-static u64 guest_id_aa64zfr0_el1(const struct kvm_vcpu *vcpu)
-{
- if (!vcpu_has_sve(vcpu))
- return 0;
-
- return read_sanitised_ftr_reg(SYS_ID_AA64ZFR0_EL1);
-}
-
-static bool access_id_aa64zfr0_el1(struct kvm_vcpu *vcpu,
- struct sys_reg_params *p,
- const struct sys_reg_desc *rd)
-{
- if (p->is_write)
- return write_to_read_only(vcpu, p, rd);
-
- p->regval = guest_id_aa64zfr0_el1(vcpu);
- return true;
-}
-
-static int get_id_aa64zfr0_el1(struct kvm_vcpu *vcpu,
- const struct sys_reg_desc *rd,
- const struct kvm_one_reg *reg, void __user *uaddr)
-{
- u64 val;
-
- val = guest_id_aa64zfr0_el1(vcpu);
- return reg_to_user(uaddr, &val, reg->id);
-}
-
-static int set_id_aa64zfr0_el1(struct kvm_vcpu *vcpu,
- const struct sys_reg_desc *rd,
- const struct kvm_one_reg *reg, void __user *uaddr)
-{
- const u64 id = sys_reg_to_index(rd);
- int err;
- u64 val;
-
- err = reg_from_user(&val, uaddr, id);
- if (err)
- return err;
-
- /* This is what we mean by invariant: you can't change it. */
- if (val != guest_id_aa64zfr0_el1(vcpu))
- return -EINVAL;
-
- return 0;
-}
-
/*
* cpufeature ID register user accessors
*
@@ -1506,7 +1467,7 @@ static const struct sys_reg_desc sys_reg_descs[] = {
ID_SANITISED(ID_AA64PFR1_EL1),
ID_UNALLOCATED(4,2),
ID_UNALLOCATED(4,3),
- { SYS_DESC(SYS_ID_AA64ZFR0_EL1), access_id_aa64zfr0_el1, .get_user = get_id_aa64zfr0_el1, .set_user = set_id_aa64zfr0_el1, },
+ ID_SANITISED(ID_AA64ZFR0_EL1),
ID_UNALLOCATED(4,5),
ID_UNALLOCATED(4,6),
ID_UNALLOCATED(4,7),
--
2.28.0