From 9a400068a1586bc4f10ee8b0443527de27d8834c Mon Sep 17 00:00:00 2001 From: Vitaly Kuznetsov Date: Fri, 20 Sep 2024 17:44:22 +0200 Subject: [PATCH] KVM: selftests: x86: Avoid using SSE/AVX instructions Some distros switched gcc to '-march=x86-64-v3' by default and while it's hard to find a CPU which doesn't support it today, many KVM selftests fail with ==== Test Assertion Failure ==== lib/x86_64/processor.c:570: Unhandled exception in guest pid=72747 tid=72747 errno=4 - Interrupted system call Unhandled exception '0x6' at guest RIP '0x4104f7' The failure is easy to reproduce elsewhere with $ make clean && CFLAGS='-march=x86-64-v3' make -j && ./x86_64/kvm_pv_test The root cause of the problem seems to be that with '-march=x86-64-v3' GCC uses AVX* instructions (VMOVQ in the example above) and without prior XSETBV() in the guest this results in #UD. It is certainly possible to add it there, e.g. the following saves the day as well: Signed-off-by: Vitaly Kuznetsov Message-ID: <20240920154422.2890096-1-vkuznets@redhat.com> Signed-off-by: Paolo Bonzini --- tools/testing/selftests/kvm/Makefile | 1 + 1 file changed, 1 insertion(+) diff --git a/tools/testing/selftests/kvm/Makefile b/tools/testing/selftests/kvm/Makefile index 960cf6a77198..e6b7e01d5708 100644 --- a/tools/testing/selftests/kvm/Makefile +++ b/tools/testing/selftests/kvm/Makefile @@ -244,6 +244,7 @@ CFLAGS += -Wall -Wstrict-prototypes -Wuninitialized -O2 -g -std=gnu99 \ -fno-stack-protector -fno-PIE -I$(LINUX_TOOL_INCLUDE) \ -I$(LINUX_TOOL_ARCH_INCLUDE) -I$(LINUX_HDR_PATH) -Iinclude \ -I$(