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SubjectRe: [PATCH v4 2/2] KVM: s390: prepare for hugepage vmalloc
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On 14.06.21 15:23, Claudio Imbrenda wrote:
> The Create Secure Configuration Ultravisor Call does not support using
> large pages for the virtual memory area. This is a hardware limitation.
>
> This patch replaces the vzalloc call with an almost equivalent call to
> the newly introduced vmalloc_no_huge function, which guarantees that
> only small pages will be used for the backing.
>
> The new call will not clear the allocated memory, but that has never
> been an actual requirement.
>
> Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
> Reviewed-by: Janosch Frank <frankja@linux.ibm.com>
> Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>
> Acked-by: Nicholas Piggin <npiggin@gmail.com>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: Nicholas Piggin <npiggin@gmail.com>
> Cc: Uladzislau Rezki (Sony) <urezki@gmail.com>
> Cc: Catalin Marinas <catalin.marinas@arm.com>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Cc: Ingo Molnar <mingo@redhat.com>
> Cc: David Rientjes <rientjes@google.com>
> Cc: Christoph Hellwig <hch@infradead.org>
> ---
> arch/s390/kvm/pv.c | 7 ++++++-
> 1 file changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/arch/s390/kvm/pv.c b/arch/s390/kvm/pv.c
> index 813b6e93dc83..c8841f476e91 100644
> --- a/arch/s390/kvm/pv.c
> +++ b/arch/s390/kvm/pv.c
> @@ -140,7 +140,12 @@ static int kvm_s390_pv_alloc_vm(struct kvm *kvm)
> /* Allocate variable storage */
> vlen = ALIGN(virt * ((npages * PAGE_SIZE) / HPAGE_SIZE), PAGE_SIZE);
> vlen += uv_info.guest_virt_base_stor_len;
> - kvm->arch.pv.stor_var = vzalloc(vlen);
> + /*
> + * The Create Secure Configuration Ultravisor Call does not support
> + * using large pages for the virtual memory area.
> + * This is a hardware limitation.
> + */
> + kvm->arch.pv.stor_var = vmalloc_no_huge(vlen);
> if (!kvm->arch.pv.stor_var)
> goto out_err;
> return 0;
>

Reviewed-by: David Hildenbrand <david@redhat.com>

--
Thanks,

David / dhildenb

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