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authorPeter Maydell <peter.maydell@linaro.org>2024-01-09 14:38:04 +0000
committerPeter Maydell <peter.maydell@linaro.org>2024-01-15 17:12:22 +0000
commit71e269fb7bd14b5e4b055b6978a4ab193e11ee8e (patch)
treedc3936ac5bb335bc7215bf9b1d174f7a0999374c /target/arm
parentd95f260aee3ea1b12779cdede7456480ea9ea3d1 (diff)
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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.c14
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 */