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| author | Alexey Kardashevskiy <aik@ozlabs.ru> | 2019-12-16 15:19:23 +1100 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2020-01-06 16:25:30 +1100 |
| commit | 17a0364cb07c173f64cefe973a93b8dbd9c61795 (patch) | |
| tree | 446be1476fe2c87a9239027891ccd96c11331743 /arch/powerpc/sysdev/mpic.c | |
| parent | 7559d3d295f3365ea7ac0c0274c05e633fe4f594 (diff) | |
powerpc/pseries/iommu: Separate FW_FEATURE_MULTITCE to put/stuff features
H_PUT_TCE_INDIRECT allows packing up to 512 TCE updates into a single
hypercall; H_STUFF_TCE can clear lots in a single hypercall too.
However, unlike H_STUFF_TCE (which writes the same TCE to all entries),
H_PUT_TCE_INDIRECT uses a 4K page with new TCEs. In a secure VM
environment this means sharing a secure VM page with a hypervisor which
we would rather avoid.
This splits the FW_FEATURE_MULTITCE feature into FW_FEATURE_PUT_TCE_IND
and FW_FEATURE_STUFF_TCE. "hcall-multi-tce" in
the "/rtas/ibm,hypertas-functions" device tree property sets both;
the "multitce=off" kernel command line parameter disables both.
This should not cause behavioural change.
Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Reviewed-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>
Tested-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20191216041924.42318-4-aik@ozlabs.ru
Diffstat (limited to 'arch/powerpc/sysdev/mpic.c')
0 files changed, 0 insertions, 0 deletions