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Blame SOURCES/kvm-accel-tcg-Test-CPUJumpCache-in-tb_jmp_cache_clear_pa.patch

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From ab68e13b7628f2348d41a4518a92508542af712f Mon Sep 17 00:00:00 2001
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From: Eric Auger <eric.auger@redhat.com>
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Date: Fri, 3 Feb 2023 18:15:10 +0100
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Subject: [PATCH 05/20] accel/tcg: Test CPUJumpCache in tb_jmp_cache_clear_page
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RH-Author: Eric Auger <eric.auger@redhat.com>
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RH-MergeRequest: 144: accel/tcg: Test CPUJumpCache in tb_jmp_cache_clear_page
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RH-Bugzilla: 2165280
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RH-Acked-by: Cornelia Huck <cohuck@redhat.com>
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RH-Acked-by: Gavin Shan <gshan@redhat.com>
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RH-Acked-by: Shaoqin Huang <None>
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RH-Commit: [1/1] 5b0863c34ba06c01c4e343d1ecd72402779c7de3 (eauger1/centos-qemu-kvm)
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Bugzilla: https://bugzilla.redhat.com/2165280
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Upstream: yes
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Brew: https://brewweb.engineering.redhat.com/brew/taskinfo?taskID=50530041
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Test: 'kvm unit test ./run_tests.sh -g debug' does not SIGSEV anymore
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After commit 4e4fa6c12d ("accel/tcg: Complete cpu initialization
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before registration"), it looks the CPUJumpCache pointer can be NULL.
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This causes a SIGSEV when running debug-wp-migration kvm unit test.
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At the first place it should be clarified why this TCG code is called
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with KVM acceleration. This may hide another bug.
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Fixes: 4e4fa6c12d ("accel/tcg: Complete cpu initialization before registration")
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Signed-off-by: Eric Auger <eric.auger@redhat.com>
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Message-Id: <20230203171510.2867451-1-eric.auger@redhat.com>
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Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
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(cherry picked from commit 99ab4d500af638ba3ebb20e8aa89d72201b70860)
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Signed-off-by: Eric Auger <eric.auger@redhat.com>
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---
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 accel/tcg/cputlb.c | 7 ++++++-
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 1 file changed, 6 insertions(+), 1 deletion(-)
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diff --git a/accel/tcg/cputlb.c b/accel/tcg/cputlb.c
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index 6f1c00682b..4244b0e4e3 100644
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--- a/accel/tcg/cputlb.c
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+++ b/accel/tcg/cputlb.c
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@@ -100,9 +100,14 @@ static void tlb_window_reset(CPUTLBDesc *desc, int64_t ns,
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 static void tb_jmp_cache_clear_page(CPUState *cpu, target_ulong page_addr)
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 {
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-    int i, i0 = tb_jmp_cache_hash_page(page_addr);
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     CPUJumpCache *jc = cpu->tb_jmp_cache;
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+    int i, i0;
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+    if (unlikely(!jc)) {
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+        return;
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+    }
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+
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+    i0 = tb_jmp_cache_hash_page(page_addr);
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     for (i = 0; i < TB_JMP_PAGE_SIZE; i++) {
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         qatomic_set(&jc->array[i0 + i].tb, NULL);
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     }
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-- 
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2.31.1
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