Re: [PATCH v3 0/3] KVM: s390: Some gaccess cleanup

Janosch Frank
2021-12-07T09:27:18Z

On 11/26/21 17:45, Janis Schoetterl-Glausch wrote:
> Cleanup s390 guest access code a bit, getting rid of some code
> duplication and improving readability.
>
> v2 -> v3
> minor changes only
> typo fixes
> whitespace
> line reordering
> picked up Reviewed-by's
>
> v1 -> v2
> separate patch for renamed variable
> fragment_len instead of seg
> expand comment of guest_range_to_gpas
> fix nits

Thanks, picked

>
> Janis Schoetterl-Glausch (3):
> KVM: s390: gaccess: Refactor gpa and length calculation
> KVM: s390: gaccess: Refactor access address range check
> KVM: s390: gaccess: Cleanup access to guest pages
>
> arch/s390/kvm/gaccess.c | 158 +++++++++++++++++++++++-----------------
> 1 file changed, 92 insertions(+), 66 deletions(-)
>
> Range-diff against v2:
> 1: 60d050210198 ! 1: e5d7d2d7a4da KVM: s390: gaccess: Refactor gpa and length calculation
> @@ Metadata
> ## Commit message ##
> KVM: s390: gaccess: Refactor gpa and length calculation
>
> - Improve readability be renaming the length variable and
> + Improve readability by renaming the length variable and
> not calculating the offset manually.
>
> Signed-off-by: Janis Schoetterl-Glausch <scgl@linux.ibm.com>
> + Reviewed-by: Janosch Frank <frankja@linux.ibm.com>
>
> ## arch/s390/kvm/gaccess.c ##
> @@ arch/s390/kvm/gaccess.c: int access_guest(struct kvm_vcpu *vcpu, unsigned long ga, u8 ar, void *data,
> @@ arch/s390/kvm/gaccess.c: int access_guest(struct kvm_vcpu *vcpu, unsigned long g
> psw_t *psw = &vcpu->arch.sie_block->gpsw;
> - unsigned long _len, nr_pages, gpa, idx;
> + unsigned long nr_pages, gpa, idx;
> -+ unsigned int fragment_len;
> unsigned long pages_array[2];
> ++ unsigned int fragment_len;
> unsigned long *pages;
> int need_ipte_lock;
> + union asce asce;
> @@ arch/s390/kvm/gaccess.c: int access_guest(struct kvm_vcpu *vcpu, unsigned long ga, u8 ar, void *data,
> ipte_lock(vcpu);
> rc = guest_page_range(vcpu, ga, ar, pages, nr_pages, asce, mode);
> 2: 7080846c8c07 ! 2: 91cadb42cbbc KVM: s390: gaccess: Refactor access address range check
> @@ Commit message
> range.
>
> Signed-off-by: Janis Schoetterl-Glausch <scgl@linux.ibm.com>
> + Reviewed-by: Janosch Frank <frankja@linux.ibm.com>
>
> ## arch/s390/kvm/gaccess.c ##
> @@ arch/s390/kvm/gaccess.c: static int low_address_protection_enabled(struct kvm_vcpu *vcpu,
> @@ arch/s390/kvm/gaccess.c: static int low_address_protection_enabled(struct kvm_vc
> + * a correct exception into the guest.
> + * The resulting gpas are stored into @gpas, unless it is NULL.
> + *
> -+ * Note: All gpas except the first one start at the beginning of a page.
> ++ * Note: All fragments except the first one start at the beginning of a page.
> + * When deriving the boundaries of a fragment from a gpa, all but the last
> + * fragment end at the end of the page.
> + *
> @@ arch/s390/kvm/gaccess.c: int access_guest(struct kvm_vcpu *vcpu, unsigned long g
> {
> psw_t *psw = &vcpu->arch.sie_block->gpsw;
> - unsigned long nr_pages, gpa, idx;
> +- unsigned long pages_array[2];
> + unsigned long nr_pages, idx;
> ++ unsigned long gpa_array[2];
> unsigned int fragment_len;
> -- unsigned long pages_array[2];
> - unsigned long *pages;
> -+ unsigned long gpa_array[2];
> + unsigned long *gpas;
> int need_ipte_lock;
> union asce asce;
> 3: c991cbdbfbd5 ! 3: f5000a22efcd KVM: s390: gaccess: Cleanup access to guest frames
> @@ Metadata
> Author: Janis Schoetterl-Glausch <scgl@linux.ibm.com>
>
> ## Commit message ##
> - KVM: s390: gaccess: Cleanup access to guest frames
> + KVM: s390: gaccess: Cleanup access to guest pages
>
> Introduce a helper function for guest frame access.
>
> Signed-off-by: Janis Schoetterl-Glausch <scgl@linux.ibm.com>
> + Reviewed-by: Janosch Frank <frankja@linux.ibm.com>
>
> ## arch/s390/kvm/gaccess.c ##
> @@ arch/s390/kvm/gaccess.c: static int guest_range_to_gpas(struct kvm_vcpu *vcpu, unsigned long ga, u8 ar,
> @@ arch/s390/kvm/gaccess.c: static int guest_range_to_gpas(struct kvm_vcpu *vcpu, u
> }
>
> +static int access_guest_page(struct kvm *kvm, enum gacc_mode mode, gpa_t gpa,
> -+ void *data, unsigned int len)
> ++ void *data, unsigned int len)
> +{
> + const unsigned int offset = offset_in_page(gpa);
> + const gfn_t gfn = gpa_to_gfn(gpa);
>
> base-commit: d25f27432f80a800a3592db128254c8140bd71bf
>