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author | Peter Maydell <peter.maydell@linaro.org> | 2024-01-09 14:38:04 +0000 |
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committer | Peter Maydell <peter.maydell@linaro.org> | 2024-01-15 17:12:22 +0000 |
commit | 71e269fb7bd14b5e4b055b6978a4ab193e11ee8e (patch) | |
tree | dc3936ac5bb335bc7215bf9b1d174f7a0999374c /target/arm | |
parent | d95f260aee3ea1b12779cdede7456480ea9ea3d1 (diff) | |
download | qemu-71e269fb7bd14b5e4b055b6978a4ab193e11ee8e.zip qemu-71e269fb7bd14b5e4b055b6978a4ab193e11ee8e.tar.gz qemu-71e269fb7bd14b5e4b055b6978a4ab193e11ee8e.tar.bz2 |
target/arm: arm_pamax() no longer needs to do feature propagation
In arm_pamax(), we need to cope with the virt board calling this
function on a CPU object which has been inited but not realize.
We used to do propagation of feature-flag implications (such as
"V7VE implies LPAE") at realize, so we have some code in arm_pamax()
which manually checks for both V7VE and LPAE feature flags.
In commit b8f7959f28c4f36 we moved the feature propagation for
almost all features from realize to post-init. That means that
now when the virt board calls arm_pamax(), the feature propagation
has been done. So we can drop the manual propagation handling
and check only for the feature we actually care about, which
is ARM_FEATURE_LPAE.
Retain the comment that the virt board is calling this function
with a not completely realized CPU object, because that is a
potential beartrap for later changes which is worth calling out.
(Note that b8f7959f28c4f36 actually fixed a bug in the arm_pamax()
handling: arm_pamax() was missing a check for ARM_FEATURE_V8, so it
incorrectly thought that the qemu-system-arm 'max' CPU did not have
LPAE and turned off 'highmem' support in the virt board. Following
b8f7959f28c4f36 qemu-system-arm 'max' is treated the same as
'cortex-a15' and other v7 LPAE CPUs, because the generic feature
propagation code does correctly propagate V8 -> V7VE -> LPAE.)
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20240109143804.1118307-1-peter.maydell@linaro.org
Diffstat (limited to 'target/arm')
-rw-r--r-- | target/arm/ptw.c | 14 |
1 files changed, 6 insertions, 8 deletions
diff --git a/target/arm/ptw.c b/target/arm/ptw.c index 2d4fa8d..5eb3577 100644 --- a/target/arm/ptw.c +++ b/target/arm/ptw.c @@ -95,7 +95,10 @@ static const uint8_t pamax_map[] = { [6] = 52, }; -/* The cpu-specific constant value of PAMax; also used by hw/arm/virt. */ +/* + * The cpu-specific constant value of PAMax; also used by hw/arm/virt. + * Note that machvirt_init calls this on a CPU that is inited but not realized! + */ unsigned int arm_pamax(ARMCPU *cpu) { if (arm_feature(&cpu->env, ARM_FEATURE_AARCH64)) { @@ -110,13 +113,8 @@ unsigned int arm_pamax(ARMCPU *cpu) return pamax_map[parange]; } - /* - * In machvirt_init, we call arm_pamax on a cpu that is not fully - * initialized, so we can't rely on the propagation done in realize. - */ - if (arm_feature(&cpu->env, ARM_FEATURE_LPAE) || - arm_feature(&cpu->env, ARM_FEATURE_V7VE)) { - /* v7 with LPAE */ + if (arm_feature(&cpu->env, ARM_FEATURE_LPAE)) { + /* v7 or v8 with LPAE */ return 40; } /* Anything else */ |