On Wed, Jul 6, 2022 at 9:05 PM Reiji Watanabe <reijiw@xxxxxxxxxx> wrote:
>
> Hi Marc,
>
> On Wed, Jul 6, 2022 at 9:43 AM Marc Zyngier <maz@xxxxxxxxxx> wrote:
> >
> > find_reg_by_id() requires a sys_reg_param as input, which most
> > users provide as a on-stack variable, but don't make any use of
> > the result.
> >
> > Provide a helper that doesn't have this requirement and simplify
> > the callers (all but one).
> >
> > Signed-off-by: Marc Zyngier <maz@xxxxxxxxxx>
> > ---
> > arch/arm64/kvm/sys_regs.c | 28 +++++++++++++++++-----------
> > arch/arm64/kvm/sys_regs.h | 4 ++++
> > arch/arm64/kvm/vgic-sys-reg-v3.c | 8 ++------
> > 3 files changed, 23 insertions(+), 17 deletions(-)
> >
> > diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
> > index c06c0477fab5..1f410283c592 100644
> > --- a/arch/arm64/kvm/sys_regs.c
> > +++ b/arch/arm64/kvm/sys_regs.c
> > @@ -2650,21 +2650,29 @@ const struct sys_reg_desc *find_reg_by_id(u64 id,
> > return find_reg(params, table, num);
> > }
> >
> > +const struct sys_reg_desc *get_reg_by_id(u64 id,
> > + const struct sys_reg_desc table[],
> > + unsigned int num)
> > +{
> > + struct sys_reg_params params;
> > +
> > + if (!index_to_params(id, ¶ms))
> > + return NULL;
> > +
> > + return find_reg(¶ms, table, num);
> > +}
>
> Since all the callers of get_reg_id() specify ARRAY_SIZE(array) for
> the 3rd argument, and I think future callers of it are also likely to
> do the same, perhaps it might be more convenient if we make get_reg_id()
> a wrapper macro like below (and rename "get_reg_by_id()" to
> "__get_reg_by_id()") ?
>
> #define get_reg_id(id, table) __get_reg_id(id, table, ARRAY_SIZE(table))
Looking at the following patches, let me withdraw this comment... Instead,
Reviewed-by: Reiji Watanabe <reijiw@xxxxxxxxxx>
Thank you,
Reiji
>
> > +
> > /* 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)
> > {
> > const struct sys_reg_desc *r;
> > - struct sys_reg_params params;
> >
> > /* We only do sys_reg for now. */
> > if ((id & KVM_REG_ARM_COPROC_MASK) != KVM_REG_ARM64_SYSREG)
> > return NULL;
> >
> > - if (!index_to_params(id, ¶ms))
> > - return NULL;
> > -
> > - r = find_reg(¶ms, sys_reg_descs, ARRAY_SIZE(sys_reg_descs));
> > + r = get_reg_by_id(id, sys_reg_descs, ARRAY_SIZE(sys_reg_descs));
> >
> > /* Not saved in the sys_reg array and not otherwise accessible? */
> > if (r && !(r->reg || r->get_user))
> > @@ -2723,11 +2731,10 @@ static int reg_to_user(void __user *uaddr, const u64 *val, u64 id)
> >
> > static int get_invariant_sys_reg(u64 id, void __user *uaddr)
> > {
> > - struct sys_reg_params params;
> > const struct sys_reg_desc *r;
> >
> > - r = find_reg_by_id(id, ¶ms, invariant_sys_regs,
> > - ARRAY_SIZE(invariant_sys_regs));
> > + r = get_reg_by_id(id, invariant_sys_regs,
> > + ARRAY_SIZE(invariant_sys_regs));
> > if (!r)
> > return -ENOENT;
> >
> > @@ -2736,13 +2743,12 @@ static int get_invariant_sys_reg(u64 id, void __user *uaddr)
> >
> > static int set_invariant_sys_reg(u64 id, void __user *uaddr)
> > {
> > - struct sys_reg_params params;
> > const struct sys_reg_desc *r;
> > int err;
> > u64 val = 0; /* Make sure high bits are 0 for 32-bit regs */
> >
> > - r = find_reg_by_id(id, ¶ms, invariant_sys_regs,
> > - ARRAY_SIZE(invariant_sys_regs));
> > + r = get_reg_by_id(id, invariant_sys_regs,
> > + ARRAY_SIZE(invariant_sys_regs));
> > if (!r)
> > return -ENOENT;
> >
> > diff --git a/arch/arm64/kvm/sys_regs.h b/arch/arm64/kvm/sys_regs.h
> > index aee8ea054f0d..ce30ed9566ae 100644
> > --- a/arch/arm64/kvm/sys_regs.h
> > +++ b/arch/arm64/kvm/sys_regs.h
> > @@ -195,6 +195,10 @@ const struct sys_reg_desc *find_reg_by_id(u64 id,
> > const struct sys_reg_desc table[],
> > unsigned int num);
> >
> > +const struct sys_reg_desc *get_reg_by_id(u64 id,
> > + 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
> > diff --git a/arch/arm64/kvm/vgic-sys-reg-v3.c b/arch/arm64/kvm/vgic-sys-reg-v3.c
> > index 07d5271e9f05..644acda33c7c 100644
> > --- a/arch/arm64/kvm/vgic-sys-reg-v3.c
> > +++ b/arch/arm64/kvm/vgic-sys-reg-v3.c
> > @@ -263,14 +263,10 @@ static const struct sys_reg_desc gic_v3_icc_reg_descs[] = {
> > int vgic_v3_has_cpu_sysregs_attr(struct kvm_vcpu *vcpu, bool is_write, u64 id,
> > u64 *reg)
> > {
> > - struct sys_reg_params params;
> > u64 sysreg = (id & KVM_DEV_ARM_VGIC_SYSREG_MASK) | KVM_REG_SIZE_U64;
> >
> > - params.regval = *reg;
> > - params.is_write = is_write;
> > -
> > - if (find_reg_by_id(sysreg, ¶ms, gic_v3_icc_reg_descs,
> > - ARRAY_SIZE(gic_v3_icc_reg_descs)))
> > + if (get_reg_by_id(sysreg, gic_v3_icc_reg_descs,
> > + ARRAY_SIZE(gic_v3_icc_reg_descs)))
> > return 0;
> >
> > return -ENXIO;
> > --
> > 2.34.1
> >
> > _______________________________________________
> > kvmarm mailing list
> > kvmarm@xxxxxxxxxxxxxxxxxxxxx
> > https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
