Nicholas Piggin [off-list ref] writes:
Excerpts from Cédric Le Goater's message of November 26, 2021 5:13 pm:
quoted
On 11/26/21 06:21, Nicholas Piggin wrote:
quoted
KVM does not support VAS so guests always print a useless error on boot
vas: HCALL(398) error -2, query_type 0, result buffer 0x57f2000
Change this to only print the message if the error is not H_FUNCTION.
Just being curious, why is it even called since "ibm,compression" should
not be exposed in the DT ?
It looks like vas does not test for it. I guess in theory there can be
other functions than compression implemented as an accelerator. Maybe
that's why?
Yeah I guess, or it's just not structured that well. The vas platform
code is a bit awkward, it's there to support drivers, but it's not
actually driver code.
I think we can probably rework it so the vas code does nothing until a
driver calls in to it.
eg. something like below.
cheers
diff --git a/arch/powerpc/platforms/pseries/vas.c b/arch/powerpc/platforms/pseries/vas.c
index b043e3936d21..dc3491fc919d 100644
--- a/arch/powerpc/platforms/pseries/vas.c
+++ b/arch/powerpc/platforms/pseries/vas.c
@@ -454,6 +454,8 @@ static const struct vas_user_win_ops vops_pseries = {
.close_win = vas_deallocate_window, /* Close window */
};
+static int pseries_vas_init(void);
+
/*
* Supporting only nx-gzip coprocessor type now, but this API code
* extended to other coprocessor types later.@@ -463,7 +465,8 @@ int vas_register_api_pseries(struct module *mod, enum vas_cop_type cop_type,
{
int rc;
- if (!copypaste_feat)
+ rc = pseries_vas_init();
+ if (rc || !copypaste_feat)
return -ENOTSUPP;
rc = vas_register_coproc_api(mod, cop_type, name, &vops_pseries);@@ -531,7 +534,7 @@ static int get_vas_capabilities(u8 feat, enum vas_cop_feat_type type,
return 0;
}
-static int __init pseries_vas_init(void)
+static int pseries_vas_init(void)
{
struct hv_vas_cop_feat_caps *hv_cop_caps;
struct hv_vas_all_caps *hv_caps;@@ -592,4 +595,3 @@ static int __init pseries_vas_init(void)
kfree(hv_caps);
return rc;
}
-machine_device_initcall(pseries, pseries_vas_init);