Re: [PATCH v7 1/9] KVM: arm64: Factor out firmware register handling from psci.c

Marc Zyngier
2022-05-03T10:36:05Z

On Tue, 03 May 2022 00:38:45 +0100,
Raghavendra Rao Ananta <rananta@google.com> wrote:
>
> Common hypercall firmware register handing is currently employed
> by psci.c. Since the upcoming patches add more of these registers,
> it's better to move the generic handling to hypercall.c for a
> cleaner presentation.
>
> While we are at it, collect all the firmware registers under
> fw_reg_ids[] to help implement kvm_arm_get_fw_num_regs() and
> kvm_arm_copy_fw_reg_indices() in a generic way. Also, define
> KVM_REG_FEATURE_LEVEL_MASK using a GENMASK instead.

Yup. See below though.

>
> No functional change intended.
>
> Signed-off-by: Raghavendra Rao Ananta <rananta@google.com>
> Reviewed-by: Oliver Upton <oupton@google.com>
> Reviewed-by: Gavin Shan <gshan@redhat.com>
> ---
> arch/arm64/kvm/guest.c | 2 +-
> arch/arm64/kvm/hypercalls.c | 185 +++++++++++++++++++++++++++++++++++
> arch/arm64/kvm/psci.c | 183 ----------------------------------
> include/kvm/arm_hypercalls.h | 7 ++
> include/kvm/arm_psci.h | 7 --
> 5 files changed, 193 insertions(+), 191 deletions(-)
>
> diff --git a/arch/arm64/kvm/guest.c b/arch/arm64/kvm/guest.c
> index 7e15b03fbdf8..0d5cca56cbda 100644
> --- a/arch/arm64/kvm/guest.c
> +++ b/arch/arm64/kvm/guest.c
> @@ -18,7 +18,7 @@
> #include <linux/string.h>
> #include <linux/vmalloc.h>
> #include <linux/fs.h>
> -#include <kvm/arm_psci.h>
> +#include <kvm/arm_hypercalls.h>
> #include <asm/cputype.h>
> #include <linux/uaccess.h>
> #include <asm/fpsimd.h>
> diff --git a/arch/arm64/kvm/hypercalls.c b/arch/arm64/kvm/hypercalls.c
> index 202b8c455724..fa6d9378d8e7 100644
> --- a/arch/arm64/kvm/hypercalls.c
> +++ b/arch/arm64/kvm/hypercalls.c
> @@ -158,3 +158,188 @@ int kvm_hvc_call_handler(struct kvm_vcpu *vcpu)
> smccc_set_retval(vcpu, val[0], val[1], val[2], val[3]);
> return 1;
> }
> +
> +static const u64 kvm_arm_fw_reg_ids[] = {
> + KVM_REG_ARM_PSCI_VERSION,
> + KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1,
> + KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2,
> + KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3,
> +};
> +
> +int kvm_arm_get_fw_num_regs(struct kvm_vcpu *vcpu)
> +{
> + return ARRAY_SIZE(kvm_arm_fw_reg_ids);
> +}
> +
> +int kvm_arm_copy_fw_reg_indices(struct kvm_vcpu *vcpu, u64 __user *uindices)
> +{
> + int i;
> +
> + for (i = 0; i < ARRAY_SIZE(kvm_arm_fw_reg_ids); i++) {
> + if (put_user(kvm_arm_fw_reg_ids[i], uindices++))
> + return -EFAULT;
> + }
> +
> + return 0;
> +}
> +
> +#define KVM_REG_FEATURE_LEVEL_WIDTH 4
> +#define KVM_REG_FEATURE_LEVEL_MASK GENMASK(KVM_REG_FEATURE_LEVEL_WIDTH, 0)

which translates in GENMASK(4, 0), which is 5 bit wide. Not what you
want.

Thanks,

M.

--
Without deviation from the norm, progress is not possible.