There are nested structs, unions, padding and flexible array members.
The interpretation of the flexible array members is all done with
pointer arithmetic, it is useful to visualize the actual memory layout.
The ascii-art drawing is compatible with ascii-art-to-unicode (aa2u) fro
m hackage.
No functional change.
Signed-off-by: Edwin Török <edwin.to...@cloud.com>
---
xen/include/public/arch-x86/pmu.h | 63 +++++++++++++++++++++++++++++++
1 file changed, 63 insertions(+)
diff --git a/xen/include/public/arch-x86/pmu.h
b/xen/include/public/arch-x86/pmu.h
index d0a99268af..8be71a88ee 100644
--- a/xen/include/public/arch-x86/pmu.h
+++ b/xen/include/public/arch-x86/pmu.h
@@ -129,6 +129,69 @@ struct xen_pmu_arch {
typedef struct xen_pmu_arch xen_pmu_arch_t;
DEFINE_XEN_GUEST_HANDLE(xen_pmu_arch_t);
+/* Memory layout:
+* .---------------------.
+* | struct xen_pmu_data |
+* +==============+=====================+=======================+ <.
+* | vcpu_id | |
+* +------------------------------------------------------------+ |
+* | pcpu_id | |
+* +------------------------------------------------------------+ |
+* | domain_id | |
+* +------------------------------------------------------------+ |
+* |##pad#######################################################| |
+* +====+=+===+==================+==============================+ |
+* | pmu| | r | regs |##pad#########################| |
+* +----. +---. (xen or guest) |##############################| |
+* | +======================+==============================+ |
+* | | pmu_flags | |
+* | +===+====================+============================+ |
+* | | l | lapic_lvtpc |############################| |
+* | +---. ###################|##pad#######################| |
+* | | ###################|############################| |
+* | +===+=+=======+=====+====+====+=======+========+======+ |
+* | | c | | | amd | | | intel | |#####| |
+* | +---+ | .-----. | .-------. |#####| |
+* | | | counter | fixed_counters |#####| |
+* | | +------------------+----------------------+#####| |
+* | | | ctrls | arch_counters |#####| |
+* | | +=====+========+===+----------------------+#####| |
+* | | | | regs[] | :| global_ctrl |#####| |
+* | | | +--------. :+----------------------+#####| |
+* | | |struct :| global_ovf_ctrl |#####| |
+* | | |xen_pmu_cntr_pair:+----------------------+#####| |
+* | | |[counters] :| global_status |#####| |
+* | | | :+----------------------+#####| |
+* | | | :| fixed_ctrl |#####| |
+* | | | :+----------------------+#####| |
+* | | | :| ds_area |#####| |
+* | | | :+----------------------+#####| |
+* | | | :| pebs_enable |#pad#| |
+* | | | :+----------------------+#####| |
+* | | | v| debugctl |#####| |
+* | | |##################+=======+========+=====+#####| |
+* | | |##################| | regs[] | :[0]|#####| |
+* | | |##################| +--------. : |#####| |
+* | | |##################| uint64_t : |#####| |
+* | | |##################| [fixed_counters] : |#####| |
+* | | |##################| : |#####| |
+* | | |##################| : |#####| |
+* | | |##################| -----------------: |#####| |
+* | | |##################| struct : |#####| |
+* | | |##################| xen_pmu_cntr_pair: |#####| |
+* | | +==================+ [arch_counters] : +=====+ |
+* | | | : | | |
+* | | | v | | |
+* | | +======================+ | |
+* | +=====================================================+ |
+* +==========================+=================================+ |
+* |############################################################| |
+* :::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: :
+* :::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: :
+* |############################################################| | PAGE_SIZE
+* +=========+==================================================+ <.
+*/
+
#endif /* __XEN_PUBLIC_ARCH_X86_PMU_H__ */
/*
* Local variables:
--
2.47.1
