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| author |   Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> | 2020-07-27 14:29:08 +0530 |
|---|---|---|
| committer |   Michael Ellerman <mpe@ellerman.id.au> | 2020-07-29 21:09:37 +1000 |
| commit | bf6b7661f41615c0815fce0a3f27acb5fc005470 (patch) | |
| tree | 4054f048ea5e51306efb8e0d2e6c50e8f564b92c /Documentation/admin-guide | |
| parent | powerpc/kvm/cma: Improve kernel log during boot (diff) | |
| download | linux-dev-bf6b7661f41615c0815fce0a3f27acb5fc005470.tar.xz linux-dev-bf6b7661f41615c0815fce0a3f27acb5fc005470.zip | |
powerpc/book3s64/radix: Add kernel command line option to disable radix GTSE
This adds a kernel command line option that can be used to disable GTSE support.
Disabling GTSE implies kernel will make hcalls to invalidate TLB entries.
This was done so that we can do VM migration between configs that enable/disable
GTSE support via hypervisor. To migrate a VM from a system that supports
GTSE to a system that doesn't, we can boot the guest with
radix_hcall_invalidate=on, thereby forcing the guest to use hcalls for TLB
invalidates.
The check for hcall availability is done in pSeries_setup_arch so that
the panic message appears on the console. This should only happen on
a hypervisor that doesn't force the guest to hash translation even
though it can't handle the radix GTSE=0 request via CAS. With
radix_hcall_invalidate=on if the hypervisor doesn't support hcall_rpt_invalidate
hcall it should force the LPAR to hash translation.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Tested-by: Bharata B Rao <bharata@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200727085908.420806-1-aneesh.kumar@linux.ibm.com
Diffstat (limited to 'Documentation/admin-guide')
| -rw-r--r-- | Documentation/admin-guide/kernel-parameters.txt | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index fb95fad81c79..3ab61cd0f89c 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -896,6 +896,10 @@ disable_radix [PPC] Disable RADIX MMU mode on POWER9 + radix_hcall_invalidate=on [PPC/PSERIES] + Disable RADIX GTSE feature and use hcall for TLB + invalidate. + disable_tlbie [PPC] Disable TLBIE instruction. Currently does not work with KVM, with HASH MMU, or with coherent accelerators. |