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06899aa5dd
It looks like a mistake to issue ISB *after* reading PAR_EL1, we should
instead perform it between the AT instruction and the reads of PAR_EL1.
As according to DDI0487J.a IJTYVP,
"When an address translation instruction is executed, explicit
synchronization is required to guarantee the result is visible to
subsequent direct reads of PAR_EL1."
Otherwise all guest_at testcases fail on my box with
==== Test Assertion Failure ====
aarch64/page_fault_test.c:142: par & 1 == 0
pid=1355864 tid=1355864 errno=4 - Interrupted system call
1 0x0000000000402853: vcpu_run_loop at page_fault_test.c:681
2 0x0000000000402cdb: run_test at page_fault_test.c:730
3 0x0000000000403897: for_each_guest_mode at guest_modes.c:100
4 0x00000000004019f3: for_each_test_and_guest_mode at page_fault_test.c:1105
5 (inlined by) main at page_fault_test.c:1131
6 0x0000ffffb153c03b: ?? ??:0
7 0x0000ffffb153c113: ?? ??:0
8 0x0000000000401aaf: _start at ??:?
0x1 != 0x0 (par & 1 != 0)
Signed-off-by: Zenghui Yu <yuzenghui@huawei.com>
Acked-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20231007124043.626-2-yuzenghui@huawei.com
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.