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-rw-r--r--meta/recipes-devtools/qemu/qemu.inc1
-rw-r--r--meta/recipes-devtools/qemu/qemu/0001-target-mips-Increase-number-of-TLB-entries-on-the-34.patch59
2 files changed, 60 insertions, 0 deletions
diff --git a/meta/recipes-devtools/qemu/qemu.inc b/meta/recipes-devtools/qemu/qemu.inc
index bbb9038961..84f600cec0 100644
--- a/meta/recipes-devtools/qemu/qemu.inc
+++ b/meta/recipes-devtools/qemu/qemu.inc
@@ -31,6 +31,7 @@ SRC_URI = "https://download.qemu.org/${BPN}-${PV}.tar.xz \
31 file://0001-qemu-Do-not-include-file-if-not-exists.patch \ 31 file://0001-qemu-Do-not-include-file-if-not-exists.patch \
32 file://find_datadir.patch \ 32 file://find_datadir.patch \
33 file://usb-fix-setup_len-init.patch \ 33 file://usb-fix-setup_len-init.patch \
34 file://0001-target-mips-Increase-number-of-TLB-entries-on-the-34.patch \
34 " 35 "
35UPSTREAM_CHECK_REGEX = "qemu-(?P<pver>\d+(\.\d+)+)\.tar" 36UPSTREAM_CHECK_REGEX = "qemu-(?P<pver>\d+(\.\d+)+)\.tar"
36 37
diff --git a/meta/recipes-devtools/qemu/qemu/0001-target-mips-Increase-number-of-TLB-entries-on-the-34.patch b/meta/recipes-devtools/qemu/qemu/0001-target-mips-Increase-number-of-TLB-entries-on-the-34.patch
new file mode 100644
index 0000000000..5227b7cbd2
--- /dev/null
+++ b/meta/recipes-devtools/qemu/qemu/0001-target-mips-Increase-number-of-TLB-entries-on-the-34.patch
@@ -0,0 +1,59 @@
1From 68fa519a6cb455005317bd61f95214b58b2f1e69 Mon Sep 17 00:00:00 2001
2From: =?UTF-8?q?Philippe=20Mathieu-Daud=C3=A9?= <f4bug@amsat.org>
3Date: Fri, 16 Oct 2020 15:20:37 +0200
4Subject: [PATCH] target/mips: Increase number of TLB entries on the 34Kf core
5 (16 -> 64)
6MIME-Version: 1.0
7Content-Type: text/plain; charset=UTF-8
8Content-Transfer-Encoding: 8bit
9
10Per "MIPS32 34K Processor Core Family Software User's Manual,
11Revision 01.13" page 8 in "Joint TLB (JTLB)" section:
12
13 "The JTLB is a fully associative TLB cache containing 16, 32,
14 or 64-dual-entries mapping up to 128 virtual pages to their
15 corresponding physical addresses."
16
17There is no particular reason to restrict the 34Kf core model to
1816 TLB entries, so raise its config to 64.
19
20This is helpful for other projects, in particular the Yocto Project:
21
22 Yocto Project uses qemu-system-mips 34Kf cpu model, to run 32bit
23 MIPS CI loop. It was observed that in this case CI test execution
24 time was almost twice longer than 64bit MIPS variant that runs
25 under MIPS64R2-generic model. It was investigated and concluded
26 that the difference in number of TLBs 16 in 34Kf case vs 64 in
27 MIPS64R2-generic is responsible for most of CI real time execution
28 difference. Because with 16 TLBs linux user-land trashes TLB more
29 and it needs to execute more instructions in TLB refill handler
30 calls, as result it runs much longer.
31
32(https://lists.gnu.org/archive/html/qemu-devel/2020-10/msg03428.html)
33
34Buglink: https://bugzilla.yoctoproject.org/show_bug.cgi?id=13992
35Reported-by: Victor Kamensky <kamensky@cisco.com>
36Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
37Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
38Message-Id: <20201016133317.553068-1-f4bug@amsat.org>
39
40Upstream-Status: Backport [https://github.com/qemu/qemu/commit/68fa519a6cb455005317bd61f95214b58b2f1e69]
41Signed-off-by: Victor Kamensky <kamensky@cisco.com>
42
43---
44 target/mips/translate_init.c.inc | 2 +-
45 1 file changed, 1 insertion(+), 1 deletion(-)
46
47Index: qemu-5.1.0/target/mips/translate_init.inc.c
48===================================================================
49--- qemu-5.1.0.orig/target/mips/translate_init.inc.c
50+++ qemu-5.1.0/target/mips/translate_init.inc.c
51@@ -254,7 +254,7 @@ const mips_def_t mips_defs[] =
52 .CP0_PRid = 0x00019500,
53 .CP0_Config0 = MIPS_CONFIG0 | (0x1 << CP0C0_AR) |
54 (MMU_TYPE_R4000 << CP0C0_MT),
55- .CP0_Config1 = MIPS_CONFIG1 | (1 << CP0C1_FP) | (15 << CP0C1_MMU) |
56+ .CP0_Config1 = MIPS_CONFIG1 | (1 << CP0C1_FP) | (63 << CP0C1_MMU) |
57 (0 << CP0C1_IS) | (3 << CP0C1_IL) | (1 << CP0C1_IA) |
58 (0 << CP0C1_DS) | (3 << CP0C1_DL) | (1 << CP0C1_DA) |
59 (1 << CP0C1_CA),