From a449ffaf9181b5a2dc705d8a06b13e0068207fd4 Mon Sep 17 00:00:00 2001 From: Will Deacon Date: Fri, 30 Jul 2021 12:42:31 +0100 Subject: [PATCH] powerpc/svm: Don't issue ultracalls if !mem_encrypt_active() Commit ad6c00283163 ("swiotlb: Free tbl memory in swiotlb_exit()") introduced a set_memory_encrypted() call to swiotlb_exit() so that the buffer pages are returned to an encrypted state prior to being freed. Sachin reports that this leads to the following crash on a Power server: [ 0.010799] software IO TLB: tearing down default memory pool [ 0.010805] ------------[ cut here ]------------ [ 0.010808] kernel BUG at arch/powerpc/kernel/interrupt.c:98! Nick spotted that this is because set_memory_encrypted() is issuing an ultracall which doesn't exist for the processor, and should therefore be gated by mem_encrypt_active() to mirror the x86 implementation. Cc: Konrad Rzeszutek Wilk Cc: Claire Chang Cc: Christoph Hellwig Cc: Robin Murphy Fixes: ad6c00283163 ("swiotlb: Free tbl memory in swiotlb_exit()") Suggested-by: Nicholas Piggin Reported-by: Sachin Sant Tested-by: Sachin Sant Tested-by: Nathan Chancellor Link: https://lore.kernel.org/r/1905CD70-7656-42AE-99E2-A31FC3812EAC@linux.vnet.ibm.com/ Signed-off-by: Will Deacon Signed-off-by: Konrad Rzeszutek Wilk --- arch/powerpc/platforms/pseries/svm.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/arch/powerpc/platforms/pseries/svm.c b/arch/powerpc/platforms/pseries/svm.c index 1d829e257996..87f001b4c4e4 100644 --- a/arch/powerpc/platforms/pseries/svm.c +++ b/arch/powerpc/platforms/pseries/svm.c @@ -63,6 +63,9 @@ void __init svm_swiotlb_init(void) int set_memory_encrypted(unsigned long addr, int numpages) { + if (!mem_encrypt_active()) + return 0; + if (!PAGE_ALIGNED(addr)) return -EINVAL; @@ -73,6 +76,9 @@ int set_memory_encrypted(unsigned long addr, int numpages) int set_memory_decrypted(unsigned long addr, int numpages) { + if (!mem_encrypt_active()) + return 0; + if (!PAGE_ALIGNED(addr)) return -EINVAL;