Hi Dave,
On 19/03/2019 17:52, Dave Martin wrote:
> In preparation for adding logic to filter out some KVM_REG_ARM_CORE
> registers from the KVM_GET_REG_LIST output, this patch factors out
> the core register enumeration into a separate function and rebuilds
> num_core_regs() on top of it.
>
> This may be a little more expensive (depending on how good a job
> the compiler does of specialising the code), but KVM_GET_REG_LIST
> is not a hot path.
>
> This will make it easier to consolidate ID filtering code in one
> place.
>
> No functional change.
>
> Signed-off-by: Dave Martin <Dave.Martin@xxxxxxx>
>
Reviewed-by: Julien Thierry <julien.thierry@xxxxxxx>
Cheers,
Julien
> ---
>
> Changes since v5:
>
> * New patch.
>
> This reimplements part of the separately-posted patch "KVM: arm64:
> Factor out KVM_GET_REG_LIST core register enumeration", minus aspects
> that potentially break the ABI.
>
> As a result, the opportunity to truly consolidate all the ID reg
> filtering in one place is deliberately left on the floor, for now.
> This will be addressed in a separate series later on.
> ---
> arch/arm64/kvm/guest.c | 33 +++++++++++++++++++++++++--------
> 1 file changed, 25 insertions(+), 8 deletions(-)
>
> diff --git a/arch/arm64/kvm/guest.c b/arch/arm64/kvm/guest.c
> index 3e38eb2..a391a61 100644
> --- a/arch/arm64/kvm/guest.c
> +++ b/arch/arm64/kvm/guest.c
> @@ -23,6 +23,7 @@
> #include <linux/err.h>
> #include <linux/kvm_host.h>
> #include <linux/module.h>
> +#include <linux/stddef.h>
> #include <linux/string.h>
> #include <linux/vmalloc.h>
> #include <linux/fs.h>
> @@ -194,9 +195,28 @@ int kvm_arch_vcpu_ioctl_set_regs(struct kvm_vcpu *vcpu, struct kvm_regs *regs)
> return -EINVAL;
> }
>
> +static int kvm_arm_copy_core_reg_indices(u64 __user *uindices)
> +{
> + unsigned int i;
> + int n = 0;
> + const u64 core_reg = KVM_REG_ARM64 | KVM_REG_SIZE_U64 | KVM_REG_ARM_CORE;
> +
> + for (i = 0; i < sizeof(struct kvm_regs) / sizeof(__u32); i++) {
> + if (uindices) {
> + if (put_user(core_reg | i, uindices))
> + return -EFAULT;
> + uindices++;
> + }
> +
> + n++;
> + }
> +
> + return n;
> +}
> +
> static unsigned long num_core_regs(void)
> {
> - return sizeof(struct kvm_regs) / sizeof(__u32);
> + return kvm_arm_copy_core_reg_indices(NULL);
> }
>
> /**
> @@ -276,15 +296,12 @@ unsigned long kvm_arm_num_regs(struct kvm_vcpu *vcpu)
> */
> int kvm_arm_copy_reg_indices(struct kvm_vcpu *vcpu, u64 __user *uindices)
> {
> - unsigned int i;
> - const u64 core_reg = KVM_REG_ARM64 | KVM_REG_SIZE_U64 | KVM_REG_ARM_CORE;
> int ret;
>
> - for (i = 0; i < sizeof(struct kvm_regs) / sizeof(__u32); i++) {
> - if (put_user(core_reg | i, uindices))
> - return -EFAULT;
> - uindices++;
> - }
> + ret = kvm_arm_copy_core_reg_indices(uindices);
> + if (ret)
> + return ret;
> + uindices += ret;
>
> ret = kvm_arm_copy_fw_reg_indices(vcpu, uindices);
> if (ret)
>
--
Julien Thierry
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