From: James Hogan Date: Thu, 29 May 2014 09:16:26 +0000 (+0100) Subject: MIPS: KVM: Use tlb_write_random X-Git-Url: http://git.lede-project.org./?a=commitdiff_plain;h=b5dfc6c10608fdf0c35a747a0a3bf3f6e40a38e1;p=openwrt%2Fstaging%2Fblogic.git MIPS: KVM: Use tlb_write_random When MIPS KVM needs to write a TLB entry for the guest it reads the CP0_Random register, uses it to generate the CP_Index, and writes the TLB entry using the TLBWI instruction (tlb_write_indexed()). However there's an instruction for that, TLBWR (tlb_write_random()) so use that instead. This happens to also fix an issue with Ingenic XBurst cores where the same TLB entry is replaced each time preventing forward progress on stores due to alternating between TLB load misses for the instruction fetch and TLB store misses. Signed-off-by: James Hogan Cc: Paolo Bonzini Cc: Gleb Natapov Cc: kvm@vger.kernel.org Cc: Ralf Baechle Cc: linux-mips@linux-mips.org Cc: Sanjay Lal Signed-off-by: Paolo Bonzini --- diff --git a/arch/mips/kvm/kvm_tlb.c b/arch/mips/kvm/kvm_tlb.c index 50ab9c4d4a5d..9d371ee0a755 100644 --- a/arch/mips/kvm/kvm_tlb.c +++ b/arch/mips/kvm/kvm_tlb.c @@ -222,16 +222,14 @@ kvm_mips_host_tlb_write(struct kvm_vcpu *vcpu, unsigned long entryhi, return -1; } - if (idx < 0) { - idx = read_c0_random() % current_cpu_data.tlbsize; - write_c0_index(idx); - mtc0_tlbw_hazard(); - } write_c0_entrylo0(entrylo0); write_c0_entrylo1(entrylo1); mtc0_tlbw_hazard(); - tlb_write_indexed(); + if (idx < 0) + tlb_write_random(); + else + tlb_write_indexed(); tlbw_use_hazard(); #ifdef DEBUG