2022-09-02 15:58:42

by Oliver Upton

Subject: [PATCH v2 3/7] KVM: arm64: Drop raz parameter from read_id_reg()

There is no longer a need for caller-specified RAZ visibility. Hoist the
call to sysreg_visible_as_raz() into read_id_reg() and drop the
parameter.

No functional change intended.

Suggested-by: Reiji Watanabe <[email protected]>
Signed-off-by: Oliver Upton <[email protected]>
---
arch/arm64/kvm/sys_regs.c | 19 ++++++-------------
1 file changed, 6 insertions(+), 13 deletions(-)

diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index 26210f3a0b27..0e20a311ea20 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -1063,13 +1063,12 @@ static bool access_arch_timer(struct kvm_vcpu *vcpu,
}

/* Read a sanitised cpufeature ID register by sys_reg_desc */
-static u64 read_id_reg(const struct kvm_vcpu *vcpu,
- struct sys_reg_desc const *r, bool raz)
+static u64 read_id_reg(const struct kvm_vcpu *vcpu, struct sys_reg_desc const *r)
{
u32 id = reg_to_encoding(r);
u64 val;

- if (raz)
+ if (sysreg_visible_as_raz(vcpu, r))
return 0;

val = read_sanitised_ftr_reg(id);
@@ -1157,12 +1156,10 @@ static bool access_id_reg(struct kvm_vcpu *vcpu,
struct sys_reg_params *p,
const struct sys_reg_desc *r)
{
- bool raz = sysreg_visible_as_raz(vcpu, r);
-
if (p->is_write)
return write_to_read_only(vcpu, p, r);

- p->regval = read_id_reg(vcpu, r, raz);
+ p->regval = read_id_reg(vcpu, r);
return true;
}

@@ -1199,7 +1196,7 @@ static int set_id_aa64pfr0_el1(struct kvm_vcpu *vcpu,
return -EINVAL;

/* We can only differ with CSV[23], and anything else is an error */
- val ^= read_id_reg(vcpu, rd, false);
+ val ^= read_id_reg(vcpu, rd);
val &= ~((0xFUL << ID_AA64PFR0_CSV2_SHIFT) |
(0xFUL << ID_AA64PFR0_CSV3_SHIFT));
if (val)
@@ -1221,19 +1218,15 @@ static int set_id_aa64pfr0_el1(struct kvm_vcpu *vcpu,
static int get_id_reg(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
u64 *val)
{
- bool raz = sysreg_visible_as_raz(vcpu, rd);
-
- *val = read_id_reg(vcpu, rd, raz);
+ *val = read_id_reg(vcpu, rd);
return 0;
}

static int set_id_reg(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
u64 val)
{
- bool raz = sysreg_visible_as_raz(vcpu, rd);
-
/* This is what we mean by invariant: you can't change it. */
- if (val != read_id_reg(vcpu, rd, raz))
+ if (val != read_id_reg(vcpu, rd))
return -EINVAL;

return 0;
--
2.37.2.789.g6183377224-goog

2022-09-07 02:39:06

by Reiji Watanabe

Subject: Re: [PATCH v2 3/7] KVM: arm64: Drop raz parameter from read_id_reg()

On Fri, Sep 2, 2022 at 8:48 AM Oliver Upton <[email protected]> wrote:
>
> There is no longer a need for caller-specified RAZ visibility. Hoist the
> call to sysreg_visible_as_raz() into read_id_reg() and drop the
> parameter.
>
> No functional change intended.
>
> Suggested-by: Reiji Watanabe <[email protected]>
> Signed-off-by: Oliver Upton <[email protected]>

Reviewed-by: Reiji Watanabe <[email protected]>