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qemu: change TLBs number to 64 in 34Kf mips cpu model
Replace OE private qemu patch with one that got upstreamed and solves the same problem: increase qemumips CI performance by increasing number of TLBs in CPU model and reduce need to run software TLB refill code. (From OE-Core rev: 89e6fc44a378cb3489376d7193672cdf94c504b6) Signed-off-by: Victor Kamensky <kamensky@cisco.com> Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org> (cherry picked from commit a99dace7463d310688f4098a51316dc0743651e2) Signed-off-by: Steve Sakoman <steve@sakoman.com> Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
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Richard Purdie
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commit
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@@ -48,6 +48,7 @@ SRC_URI = "https://download.qemu.org/${BPN}-${PV}.tar.xz \
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file://CVE-2020-14364.patch \
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file://CVE-2020-14415.patch \
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file://CVE-2020-16092.patch \
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file://0001-target-mips-Increase-number-of-TLB-entries-on-the-34.patch \
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"
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UPSTREAM_CHECK_REGEX = "qemu-(?P<pver>\d+(\.\d+)+)\.tar"
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@@ -0,0 +1,59 @@
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From 68fa519a6cb455005317bd61f95214b58b2f1e69 Mon Sep 17 00:00:00 2001
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From: =?UTF-8?q?Philippe=20Mathieu-Daud=C3=A9?= <f4bug@amsat.org>
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Date: Fri, 16 Oct 2020 15:20:37 +0200
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Subject: [PATCH] target/mips: Increase number of TLB entries on the 34Kf core
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(16 -> 64)
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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Per "MIPS32 34K Processor Core Family Software User's Manual,
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Revision 01.13" page 8 in "Joint TLB (JTLB)" section:
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"The JTLB is a fully associative TLB cache containing 16, 32,
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or 64-dual-entries mapping up to 128 virtual pages to their
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corresponding physical addresses."
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There is no particular reason to restrict the 34Kf core model to
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16 TLB entries, so raise its config to 64.
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This is helpful for other projects, in particular the Yocto Project:
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Yocto Project uses qemu-system-mips 34Kf cpu model, to run 32bit
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MIPS CI loop. It was observed that in this case CI test execution
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time was almost twice longer than 64bit MIPS variant that runs
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under MIPS64R2-generic model. It was investigated and concluded
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that the difference in number of TLBs 16 in 34Kf case vs 64 in
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MIPS64R2-generic is responsible for most of CI real time execution
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difference. Because with 16 TLBs linux user-land trashes TLB more
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and it needs to execute more instructions in TLB refill handler
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calls, as result it runs much longer.
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(https://lists.gnu.org/archive/html/qemu-devel/2020-10/msg03428.html)
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Buglink: https://bugzilla.yoctoproject.org/show_bug.cgi?id=13992
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Reported-by: Victor Kamensky <kamensky@cisco.com>
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Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
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Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
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Message-Id: <20201016133317.553068-1-f4bug@amsat.org>
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Upstream-Status: Backport [https://github.com/qemu/qemu/commit/68fa519a6cb455005317bd61f95214b58b2f1e69]
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Signed-off-by: Victor Kamensky <kamensky@cisco.com>
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---
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target/mips/translate_init.c.inc | 2 +-
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1 file changed, 1 insertion(+), 1 deletion(-)
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Index: qemu-5.1.0/target/mips/translate_init.inc.c
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===================================================================
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--- qemu-5.1.0.orig/target/mips/translate_init.inc.c
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+++ qemu-5.1.0/target/mips/translate_init.inc.c
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@@ -254,7 +254,7 @@ const mips_def_t mips_defs[] =
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.CP0_PRid = 0x00019500,
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.CP0_Config0 = MIPS_CONFIG0 | (0x1 << CP0C0_AR) |
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(MMU_TYPE_R4000 << CP0C0_MT),
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- .CP0_Config1 = MIPS_CONFIG1 | (1 << CP0C1_FP) | (15 << CP0C1_MMU) |
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+ .CP0_Config1 = MIPS_CONFIG1 | (1 << CP0C1_FP) | (63 << CP0C1_MMU) |
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(0 << CP0C1_IS) | (3 << CP0C1_IL) | (1 << CP0C1_IA) |
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(0 << CP0C1_DS) | (3 << CP0C1_DL) | (1 << CP0C1_DA) |
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(1 << CP0C1_CA),
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