On Sun, 16 Feb 2020 18:53:21 +0000
Marc Zyngier <maz@xxxxxxxxxx> wrote:
Hi,
> Our current ID register filtering is starting to be a mess of if()
> statements, and isn't going to get any saner.
>
> Let's turn it into a switch(), which has a chance of being more
> readable.
Indeed, much better now.
> Signed-off-by: Marc Zyngier <maz@xxxxxxxxxx>
Reviewed-by: Andre Przywara <andre.przywara@xxxxxxx>
Thanks,
Andre
> ---
> arch/arm64/kvm/sys_regs.c | 22 +++++++++++++++-------
> 1 file changed, 15 insertions(+), 7 deletions(-)
>
> diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
> index da82c4b03aab..682fedd7700f 100644
> --- a/arch/arm64/kvm/sys_regs.c
> +++ b/arch/arm64/kvm/sys_regs.c
> @@ -9,6 +9,7 @@
> * Christoffer Dall <c.dall@xxxxxxxxxxxxxxxxxxxxxx>
> */
>
> +#include <linux/bitfield.h>
> #include <linux/bsearch.h>
> #include <linux/kvm_host.h>
> #include <linux/mm.h>
> @@ -1070,6 +1071,8 @@ static bool access_arch_timer(struct kvm_vcpu *vcpu,
> return true;
> }
>
> +#define FEATURE(x) (GENMASK_ULL(x##_SHIFT + 3, x##_SHIFT))
> +
> /* 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)
> @@ -1078,13 +1081,18 @@ static u64 read_id_reg(const struct kvm_vcpu *vcpu,
> (u32)r->CRn, (u32)r->CRm, (u32)r->Op2);
> u64 val = raz ? 0 : read_sanitised_ftr_reg(id);
>
> - if (id == SYS_ID_AA64PFR0_EL1 && !vcpu_has_sve(vcpu)) {
> - val &= ~(0xfUL << ID_AA64PFR0_SVE_SHIFT);
> - } else if (id == SYS_ID_AA64ISAR1_EL1 && !vcpu_has_ptrauth(vcpu)) {
> - val &= ~((0xfUL << ID_AA64ISAR1_APA_SHIFT) |
> - (0xfUL << ID_AA64ISAR1_API_SHIFT) |
> - (0xfUL << ID_AA64ISAR1_GPA_SHIFT) |
> - (0xfUL << ID_AA64ISAR1_GPI_SHIFT));
> + switch (id) {
> + case SYS_ID_AA64PFR0_EL1:
> + if (!vcpu_has_sve(vcpu))
> + val &= ~FEATURE(ID_AA64PFR0_SVE);
> + break;
> + case SYS_ID_AA64ISAR1_EL1:
> + if (!vcpu_has_ptrauth(vcpu))
> + val &= ~(FEATURE(ID_AA64ISAR1_APA) |
> + FEATURE(ID_AA64ISAR1_API) |
> + FEATURE(ID_AA64ISAR1_GPA) |
> + FEATURE(ID_AA64ISAR1_GPI));
> + break;
> }
>
> return val;
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