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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 /arch/powerpc/kernel/prom_init.c | |
| 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 'arch/powerpc/kernel/prom_init.c')
| -rw-r--r-- | arch/powerpc/kernel/prom_init.c | 13 |
1 files changed, 9 insertions, 4 deletions
diff --git a/arch/powerpc/kernel/prom_init.c b/arch/powerpc/kernel/prom_init.c index cbc605cfdec0..f279a1f58fa7 100644 --- a/arch/powerpc/kernel/prom_init.c +++ b/arch/powerpc/kernel/prom_init.c @@ -169,6 +169,7 @@ static unsigned long __prombss prom_tce_alloc_end; #ifdef CONFIG_PPC_PSERIES static bool __prombss prom_radix_disable; +static bool __prombss prom_radix_gtse_disable; static bool __prombss prom_xive_disable; #endif @@ -823,6 +824,12 @@ static void __init early_cmdline_parse(void) if (prom_radix_disable) prom_debug("Radix disabled from cmdline\n"); + opt = prom_strstr(prom_cmd_line, "radix_hcall_invalidate=on"); + if (opt) { + prom_radix_gtse_disable = true; + prom_debug("Radix GTSE disabled from cmdline\n"); + } + opt = prom_strstr(prom_cmd_line, "xive=off"); if (opt) { prom_xive_disable = true; @@ -1285,10 +1292,8 @@ static void __init prom_parse_platform_support(u8 index, u8 val, prom_parse_mmu_model(val & OV5_FEAT(OV5_MMU_SUPPORT), support); break; case OV5_INDX(OV5_RADIX_GTSE): /* Radix Extensions */ - if (val & OV5_FEAT(OV5_RADIX_GTSE)) { - prom_debug("Radix - GTSE supported\n"); - support->radix_gtse = true; - } + if (val & OV5_FEAT(OV5_RADIX_GTSE)) + support->radix_gtse = !prom_radix_gtse_disable; break; case OV5_INDX(OV5_XIVE_SUPPORT): /* Interrupt mode */ prom_parse_xive_model(val & OV5_FEAT(OV5_XIVE_SUPPORT), |