On 19/03/2019 15:04, Suraj Jitindar Singh wrote:
> Implement a virtual mode handler for the H_CALL H_PAGE_INIT which can be
> used to zero or copy a guest page. The page is defined to be 4k and must
> be 4k aligned.
>
> The in-kernel handler halves the time to handle this H_CALL compared to
> handling it in userspace for a radix guest.
>
> Signed-off-by: Suraj Jitindar Singh <sjitindarsingh@xxxxxxxxx>
> ---
> arch/powerpc/kvm/book3s_hv.c | 39 +++++++++++++++++++++++++++++++++++++++
> 1 file changed, 39 insertions(+)
>
> diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
> index 7179ea783f4f..fa29cc4900c2 100644
> --- a/arch/powerpc/kvm/book3s_hv.c
> +++ b/arch/powerpc/kvm/book3s_hv.c
> @@ -883,6 +883,39 @@ static int kvmppc_copy_guest(struct kvm *kvm, gpa_t to, gpa_t from,
> return 0;
> }
>
> +static int kvmppc_h_page_init(struct kvm_vcpu *vcpu, unsigned long flags,
> + unsigned long dest, unsigned long src)
> +{
> + int ret = H_FUNCTION;
> + u64 pg_sz = 1UL << 12; /* 4K page size */
> + u64 pg_mask = pg_sz - 1;
Ditch pg_sz and just use SZ_4K? The page size is not going to change
here ever.
> +
> + /* Check for invalid flags (H_PAGE_SET_LOANED covers all CMO flags) */
> + if (flags & ~(H_ICACHE_INVALIDATE | H_ICACHE_SYNCHRONIZE |
> + H_ZERO_PAGE | H_COPY_PAGE | H_PAGE_SET_LOANED))
> + return H_PARAMETER;
> +
> + /* dest (and src if copy_page flag set) must be page aligned */
> + if ((dest & pg_mask) || ((flags & H_COPY_PAGE) && (src & pg_mask)))
> + return H_PARAMETER;
> +
> + /* zero and/or copy the page as determined by the flags */
> + if (flags & H_ZERO_PAGE) {
> + ret = kvm_clear_guest(vcpu->kvm, dest, pg_sz);
> + if (ret < 0)
> + return H_PARAMETER;
> + }
> + if (flags & H_COPY_PAGE) {
If H_COPY_PAGE is set, is there any good reason to do kvm_clear_guest
first even if H_ZERO_PAGE is set? It should not happen in practice and
it is no harm but also no sense.
> + ret = kvmppc_copy_guest(vcpu->kvm, dest, src, pg_sz);
> + if (ret < 0)
> + return H_PARAMETER;
> + }
else if (src)
return H_PARAMETER;
> +
> + /* We can ignore the remaining flags */
> +
> + return H_SUCCESS;
> +}
> +
> static int kvm_arch_vcpu_yield_to(struct kvm_vcpu *target)
> {
> struct kvmppc_vcore *vcore = target->arch.vcore;
> @@ -1083,6 +1116,11 @@ int kvmppc_pseries_do_hcall(struct kvm_vcpu *vcpu)
> if (nesting_enabled(vcpu->kvm))
> ret = kvmhv_copy_tofrom_guest_nested(vcpu);
> break;
> + case H_PAGE_INIT:
> + ret = kvmppc_h_page_init(vcpu, kvmppc_get_gpr(vcpu, 4),
> + kvmppc_get_gpr(vcpu, 5),
> + kvmppc_get_gpr(vcpu, 6));
> + break;
> default:
> return RESUME_HOST;
> }
> @@ -1127,6 +1165,7 @@ static int kvmppc_hcall_impl_hv(unsigned long cmd)
> case H_IPOLL:
> case H_XIRR_X:
> #endif
> + case H_PAGE_INIT:
> return 1;
> }
>
>
--
Alexey
