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Ignore VAS update for DLPAR

Mamatha Inamdar requested to merge mainamdar/centos-stream-9:bz2185505 into main

Bugzilla: https://bugzilla.redhat.com/2185505

Build Info: https://brewweb.engineering.redhat.com/brew/taskinfo?taskID=51927724

Tested: Verified Brew build test kernel RPMs and confirmed issue is resovled

commit eca9f6e6f83b6725b84e1c76fdde19b003cff0eb Author: Haren Myneni haren@linux.ibm.com Date: Mon Mar 20 19:50:08 2023 -0700

powerpc/pseries/vas: Ignore VAS update for DLPAR if copy/paste is not enabled

The hypervisor supports user-mode NX from Power10.

pseries_vas_dlpar_cpu() is called from lparcfg_write() to update VAS
windows for DLPAR event in shared processor mode and the kernel gets
-ENOTSUPP for HCALLs if the user-mode NX is not supported. The current
VAS implementation also supports only with Radix page tables. Whereas in
dedicated processor mode, pseries_vas_notifier() is registered only if
the copy/paste feature is enabled. So instead of displaying HCALL error
messages, update VAS capabilities if the copy/paste feature is
available.

This patch ignores updating VAS capabilities in pseries_vas_dlpar_cpu()
and returns success if the copy/paste feature is not enabled. Then
lparcfg_write() completes the processor DLPAR operations without any
failures.

Fixes: 2147783d6bf0 ("powerpc/pseries: Use lparcfg to reconfig VAS windows for DLPAR CPU")
Cc: stable@vger.kernel.org # v6.1+
Signed-off-by: Haren Myneni <haren@linux.ibm.com>
Reviewed-by: Nathan Lynch <nathanl@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/1d0e727e7dbd9a28627ef08ca9df9c86a50175e2.camel@linux.ibm.com

Signed-off-by: Mamatha Inamdar minamdar@redhat.com

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