Nicholas Piggin <npiggin@xxxxxxxxx> writes:
> KVM currently validates the size of the VPA registered by the client
> against sizeof(struct lppaca), however we align (and therefore size)
> that struct to 1kB to avoid crossing a 4kB boundary in the client.
>
> PAPR calls for sizes >= 640 bytes to be accepted. Hard code this with
> a comment.
>
> Signed-off-by: Nicholas Piggin <npiggin@xxxxxxxxx>
> ---
> arch/powerpc/kvm/book3s_hv.c | 8 +++++++-
> 1 file changed, 7 insertions(+), 1 deletion(-)
This one should go via Paul.
Hopefully he can just pick it up.
cheers
> diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
> index 359c79cdf0cc..1182cfd79857 100644
> --- a/arch/powerpc/kvm/book3s_hv.c
> +++ b/arch/powerpc/kvm/book3s_hv.c
> @@ -485,7 +485,13 @@ static unsigned long do_h_register_vpa(struct kvm_vcpu *vcpu,
>
> switch (subfunc) {
> case H_VPA_REG_VPA: /* register VPA */
> - if (len < sizeof(struct lppaca))
> + /*
> + * The size of our lppaca is 1kB because of the way we align
> + * it for the guest to avoid crossing a 4kB boundary. We only
> + * use 640 bytes of the structure though, so we should accept
> + * clients that set a size of 640.
> + */
> + if (len < 640)
> break;
> vpap = &tvcpu->arch.vpa;
> err = 0;
> --
> 2.13.3
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