From: James Hogan Date: Fri, 12 Jul 2013 10:26:11 +0000 (+0000) Subject: MIPS: KVM: Mark KVM_GUEST (T&E KVM) as BROKEN_ON_SMP X-Git-Tag: firefly_0821_release~176^2~5668^2~2 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=f2a5b1d78c076c525d20176d227faf2e6a20257c;p=firefly-linux-kernel-4.4.55.git MIPS: KVM: Mark KVM_GUEST (T&E KVM) as BROKEN_ON_SMP Make KVM_GUEST depend on BROKEN_ON_SMP so that it cannot be enabled with SMP. SMP kernels use ll/sc instructions for an atomic section in the tlb fill handler, with a tlbp instruction contained in the middle. This cannot be emulated with trap & emulate KVM because the tlbp instruction traps and the eret to return to the guest code clears the LLbit which makes the sc instruction always fail. Signed-off-by: James Hogan Cc: Sanjay Lal Cc: Ralf Baechle Cc: David Daney Cc: linux-mips@linux-mips.org Cc: kvm@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/5588/ Signed-off-by: Ralf Baechle --- diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig index 4758a8fd3e99..c3abed332301 100644 --- a/arch/mips/Kconfig +++ b/arch/mips/Kconfig @@ -1702,6 +1702,7 @@ endchoice config KVM_GUEST bool "KVM Guest Kernel" + depends on BROKEN_ON_SMP help Select this option if building a guest kernel for KVM (Trap & Emulate) mode