6.1-stable review patch. If anyone has any objections, please let me know.
------------------
From: Jack Wang <jinpu.wang@xxxxxxxxx>
commit 3d7d72a34e05b23e21bafc8bfb861e73c86b31f3 upstream.
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@xxxxxxxxx>
Signed-off-by: Jack Wang <jinpu.wang@xxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Tested-by: Yu Zhang <yu.zhang@xxxxxxxxx>
Reviewed-by: Jarkko Sakkinen <jarkko@xxxxxxxxxx>
Reviewed-by: Kai Huang <kai.huang@xxxxxxxxx>
Acked-by: Haitao Huang <haitao.huang@xxxxxxxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/x86/kernel/cpu/sgx/virt.c | 3 +++
1 file changed, 3 insertions(+)
--- 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
continue;
xa_erase(&vepc->page_array, index);
+ cond_resched();
}
/*
@@ -222,6 +223,7 @@ static int sgx_vepc_release(struct inode
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
if (sgx_vepc_free_page(epc_page))
list_add_tail(&epc_page->list, &secs_pages);
+ cond_resched();
}
if (!list_empty(&secs_pages))
