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| author | Shawn Anastasio <shawn@anastas.io> | 2020-08-21 13:55:57 -0500 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2020-08-24 14:12:54 +1000 |
| commit | 9b725a90a8f127802e19466d4e336e701bcea0d2 (patch) | |
| tree | 03641564d277fa36483be5cef7fce5deb8454572 /arch/powerpc | |
| parent | 12564485ed8caac3c18572793ec01330792c7191 (diff) | |
| download | lwn-9b725a90a8f127802e19466d4e336e701bcea0d2.tar.gz lwn-9b725a90a8f127802e19466d4e336e701bcea0d2.zip | |
powerpc/64s: Disallow PROT_SAO in LPARs by default
Since migration of guests using SAO to ISA 3.1 hosts may cause issues,
disable PROT_SAO in LPARs by default and introduce a new Kconfig option
PPC_PROT_SAO_LPAR to allow users to enable it if desired.
Signed-off-by: Shawn Anastasio <shawn@anastas.io>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200821185558.35561-3-shawn@anastas.io
Diffstat (limited to 'arch/powerpc')
| -rw-r--r-- | arch/powerpc/Kconfig | 12 | ||||
| -rw-r--r-- | arch/powerpc/include/asm/mman.h | 9 |
2 files changed, 19 insertions, 2 deletions
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig index 1f48bbfb3ce9..65bed1fdeaad 100644 --- a/arch/powerpc/Kconfig +++ b/arch/powerpc/Kconfig @@ -860,6 +860,18 @@ config PPC_SUBPAGE_PROT If unsure, say N here. +config PPC_PROT_SAO_LPAR + bool "Support PROT_SAO mappings in LPARs" + depends on PPC_BOOK3S_64 + help + This option adds support for PROT_SAO mappings from userspace + inside LPARs on supported CPUs. + + This may cause issues when performing guest migration from + a CPU that supports SAO to one that does not. + + If unsure, say N here. + config PPC_COPRO_BASE bool diff --git a/arch/powerpc/include/asm/mman.h b/arch/powerpc/include/asm/mman.h index 4ba303ea27f5..7cb6d18f5cd6 100644 --- a/arch/powerpc/include/asm/mman.h +++ b/arch/powerpc/include/asm/mman.h @@ -40,8 +40,13 @@ static inline bool arch_validate_prot(unsigned long prot, unsigned long addr) { if (prot & ~(PROT_READ | PROT_WRITE | PROT_EXEC | PROT_SEM | PROT_SAO)) return false; - if ((prot & PROT_SAO) && !cpu_has_feature(CPU_FTR_SAO)) - return false; + if (prot & PROT_SAO) { + if (!cpu_has_feature(CPU_FTR_SAO)) + return false; + if (firmware_has_feature(FW_FEATURE_LPAR) && + !IS_ENABLED(CONFIG_PPC_PROT_SAO_LPAR)) + return false; + } return true; } #define arch_validate_prot arch_validate_prot |