On Mon, 2021-06-14 at 13:39 +1000, Nicholas Piggin wrote: > Excerpts from Haren Myneni's message of June 13, 2021 9:04 pm: > > The hypervisor provides different capabilities that it supports > > to define the user space NX request. These capabilities are > > recommended minimum compression / decompression lengths and the > > maximum request buffer size in bytes. > > > > Changes to get NX overall capabilities which points to the > > specific features that the hypervisor supports. Then retrieve > > the capabilities for the specific feature (available only > > for NXGZIP). > > So what does this give you which you didn't have before? Should > this go before the previous patch that enables the interface for > guests, > or is there some functional-yet-degraded mode that is available > without > this patch? > > I would suggest even if this is the case to switch ordering of the > patches so as to reduce the matrix of functionality that userspace > sees > when bisecting. Unless you specifically want this kind of > bisectability, > in which case make that explicit in the changelog. Thanks for your suggestions. I will incorporate them and post next revision. The user space request buffer length should not be more than req_max_processed_len (available through sysfs). Otherwise NX will return the request with RMA_Reject. Whereasas min_compress_len and min_decompress_len are recommended values. We can add this patch and the last one (crypto/nx: Add sysfs interface to export NX capabilities) before the actual enablement ("crypto/nx: Register and unregisterVAS interface on PowerVM"" Thanks Haren > > Thanks, > Nick > > > Signed-off-by: Haren Myneni <haren@xxxxxxxxxxxxx> > > Acked-by: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx> > > --- > > drivers/crypto/nx/nx-common-pseries.c | 86 > > +++++++++++++++++++++++++++ > > 1 file changed, 86 insertions(+) > > > > diff --git a/drivers/crypto/nx/nx-common-pseries.c > > b/drivers/crypto/nx/nx-common-pseries.c > > index 9a40fca8a9e6..60b5049ec9f7 100644 > > --- a/drivers/crypto/nx/nx-common-pseries.c > > +++ b/drivers/crypto/nx/nx-common-pseries.c > > @@ -9,6 +9,7 @@ > > */ > > > > #include <asm/vio.h> > > +#include <asm/hvcall.h> > > #include <asm/vas.h> > > > > #include "nx-842.h" > > @@ -20,6 +21,29 @@ MODULE_DESCRIPTION("842 H/W Compression driver > > for IBM Power processors"); > > MODULE_ALIAS_CRYPTO("842"); > > MODULE_ALIAS_CRYPTO("842-nx"); > > > > +/* > > + * Coprocessor type specific capabilities from the hypervisor. > > + */ > > +struct hv_nx_ct_caps { > > + __be64 descriptor; > > + __be64 req_max_processed_len; /* Max bytes in one GZIP > > request */ > > + __be64 min_compress_len; /* Min compression size in > > bytes */ > > + __be64 min_decompress_len; /* Min decompression size > > in bytes */ > > +} __packed __aligned(0x1000); > > + > > +/* > > + * Coprocessor type specific capabilities. > > + */ > > +struct nx_ct_caps { > > + u64 descriptor; > > + u64 req_max_processed_len; /* Max bytes in one GZIP request */ > > + u64 min_compress_len; /* Min compression in bytes */ > > + u64 min_decompress_len; /* Min decompression in bytes */ > > +}; > > + > > +static u64 caps_feat; > > +static struct nx_ct_caps nx_ct_caps; > > + > > static struct nx842_constraints nx842_pseries_constraints = { > > .alignment = DDE_BUFFER_ALIGN, > > .multiple = DDE_BUFFER_LAST_MULT, > > @@ -1066,6 +1090,64 @@ static void nx842_remove(struct vio_dev > > *viodev) > > kfree(old_devdata); > > } > > > > +/* > > + * Get NX capabilities from the hypervisor. > > + * Only NXGZIP capabilities are provided by the hypersvisor right > > + * now and these values are available to user space with sysfs. > > + */ > > +static void __init nxct_get_capabilities(void) > > +{ > > + struct hv_vas_all_caps *hv_caps; > > + struct hv_nx_ct_caps *hv_nxc; > > + int rc; > > + > > + hv_caps = kmalloc(sizeof(*hv_caps), GFP_KERNEL); > > + if (!hv_caps) > > + return; > > + /* > > + * Get NX overall capabilities with feature type=0 > > + */ > > + rc = h_query_vas_capabilities(H_QUERY_NX_CAPABILITIES, 0, > > + (u64)virt_to_phys(hv_caps)); > > + if (rc) > > + goto out; > > + > > + caps_feat = be64_to_cpu(hv_caps->feat_type); > > + /* > > + * NX-GZIP feature available > > + */ > > + if (caps_feat & VAS_NX_GZIP_FEAT_BIT) { > > + hv_nxc = kmalloc(sizeof(*hv_nxc), GFP_KERNEL); > > + if (!hv_nxc) > > + goto out; > > + /* > > + * Get capabilities for NX-GZIP feature > > + */ > > + rc = h_query_vas_capabilities(H_QUERY_NX_CAPABILITIES, > > + VAS_NX_GZIP_FEAT, > > + (u64)virt_to_phys(hv_ > > nxc)); > > + } else { > > + pr_err("NX-GZIP feature is not available\n"); > > + rc = -EINVAL; > > + } > > + > > + if (!rc) { > > + nx_ct_caps.descriptor = be64_to_cpu(hv_nxc- > > >descriptor); > > + nx_ct_caps.req_max_processed_len = > > + be64_to_cpu(hv_nxc- > > >req_max_processed_len); > > + nx_ct_caps.min_compress_len = > > + be64_to_cpu(hv_nxc->min_compress_len); > > + nx_ct_caps.min_decompress_len = > > + be64_to_cpu(hv_nxc- > > >min_decompress_len); > > + } else { > > + caps_feat = 0; > > + } > > + > > + kfree(hv_nxc); > > +out: > > + kfree(hv_caps); > > +} > > + > > static const struct vio_device_id nx842_vio_driver_ids[] = { > > {"ibm,compression-v1", "ibm,compression"}, > > {"", ""}, > > @@ -1093,6 +1175,10 @@ static int __init nx842_pseries_init(void) > > return -ENOMEM; > > > > RCU_INIT_POINTER(devdata, new_devdata); > > + /* > > + * Get NX capabilities from the hypervisor. > > + */ > > + nxct_get_capabilities(); > > > > ret = vio_register_driver(&nx842_vio_driver); > > if (ret) { > > -- > > 2.18.2 > > > > > >