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authorJack Wang <jinpu.wang@ionos.com>2023-09-06 15:17:12 +0200
committerIngo Molnar <mingo@kernel.org>2023-09-06 23:55:09 +0200
commit3d7d72a34e05b23e21bafc8bfb861e73c86b31f3 (patch)
treea17c8b3aa649bdc54dbbaa8b903fa89a49ad5ca6
parent659df86a7b2fe98feb5f4ec880e694caaebd27ae (diff)
x86/sgx: Break up long non-preemptible delays in sgx_vepc_release()
On large enclaves we hit the softlockup warning with following call trace: xa_erase() sgx_vepc_release() __fput() task_work_run() do_exit() The latency issue is similar to the one fixed in: 8795359e35bc ("x86/sgx: Silence softlockup detection when releasing large enclaves") The test system has 64GB of enclave memory, and all is assigned to a single VM. Release of 'vepc' takes a longer time and causes long latencies, which triggers the softlockup warning. Add cond_resched() to give other tasks a chance to run and reduce latencies, which also avoids the softlockup detector. [ mingo: Rewrote the changelog. ] Fixes: 540745ddbc70 ("x86/sgx: Introduce virtual EPC for use by KVM guests") Reported-by: Yu Zhang <yu.zhang@ionos.com> Signed-off-by: Jack Wang <jinpu.wang@ionos.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Tested-by: Yu Zhang <yu.zhang@ionos.com> Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org> Reviewed-by: Kai Huang <kai.huang@intel.com> Acked-by: Haitao Huang <haitao.huang@linux.intel.com> Cc: stable@vger.kernel.org
-rw-r--r--arch/x86/kernel/cpu/sgx/virt.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/arch/x86/kernel/cpu/sgx/virt.c b/arch/x86/kernel/cpu/sgx/virt.c
index c3e37eaec8ec..7aaa3652e31d 100644
--- a/arch/x86/kernel/cpu/sgx/virt.c
+++ b/arch/x86/kernel/cpu/sgx/virt.c
@@ -204,6 +204,7 @@ static int sgx_vepc_release(struct inode *inode, struct file *file)
continue;
xa_erase(&vepc->page_array, index);
+ cond_resched();
}
/*
@@ -222,6 +223,7 @@ static int sgx_vepc_release(struct inode *inode, struct file *file)
list_add_tail(&epc_page->list, &secs_pages);
xa_erase(&vepc->page_array, index);
+ cond_resched();
}
/*
@@ -243,6 +245,7 @@ static int sgx_vepc_release(struct inode *inode, struct file *file)
if (sgx_vepc_free_page(epc_page))
list_add_tail(&epc_page->list, &secs_pages);
+ cond_resched();
}
if (!list_empty(&secs_pages))