linux-kernel - [PATCH 3.12 001/127] Revert "KVM: MIPS: Drop other CPU ASIDs on guest MMU changes"

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Date:   Fri, 25 Nov 2016 09:28:34 +0100
From:   Jiri Slaby <jslaby@...e.cz>
To:     stable@...r.kernel.org
Cc:     linux-kernel@...r.kernel.org, Jiri Slaby <jslaby@...e.cz>,
        James Hogan <james.hogan@...tec.com>
Subject: [PATCH 3.12 001/127] Revert "KVM: MIPS: Drop other CPU ASIDs on guest MMU changes"

3.12-stable review patch.  If anyone has any objections, please let me know.

===============

This reverts commit 168e5ebbd63eaf2557b5e37be1afb8c143de2380, which is
upstream commit 91e4f1b6073dd680d86cdb7e42d7cccca9db39d8. It caused
build failures as it was improperly backported. New version is
approaching, so revert this bad one.

Signed-off-by: Jiri Slaby <jslaby@...e.cz>
Cc: James Hogan <james.hogan@...tec.com>
---
 arch/mips/kvm/kvm_mips_emul.c | 57 +++----------------------------------------
 1 file changed, 4 insertions(+), 53 deletions(-)

diff --git a/arch/mips/kvm/kvm_mips_emul.c b/arch/mips/kvm/kvm_mips_emul.c
index 8ab9958767bb..9f7643874fba 100644
--- a/arch/mips/kvm/kvm_mips_emul.c
+++ b/arch/mips/kvm/kvm_mips_emul.c
@@ -310,47 +310,6 @@ enum emulation_result kvm_mips_emul_tlbr(struct kvm_vcpu *vcpu)
 	return er;
 }
 
-/**
- * kvm_mips_invalidate_guest_tlb() - Indicates a change in guest MMU map.
- * @vcpu:	VCPU with changed mappings.
- * @tlb:	TLB entry being removed.
- *
- * This is called to indicate a single change in guest MMU mappings, so that we
- * can arrange TLB flushes on this and other CPUs.
- */
-static void kvm_mips_invalidate_guest_tlb(struct kvm_vcpu *vcpu,
-					  struct kvm_mips_tlb *tlb)
-{
-	int cpu, i;
-	bool user;
-
-	/* No need to flush for entries which are already invalid */
-	if (!((tlb->tlb_lo[0] | tlb->tlb_lo[1]) & ENTRYLO_V))
-		return;
-	/* User address space doesn't need flushing for KSeg2/3 changes */
-	user = tlb->tlb_hi < KVM_GUEST_KSEG0;
-
-	preempt_disable();
-
-	/*
-	 * Probe the shadow host TLB for the entry being overwritten, if one
-	 * matches, invalidate it
-	 */
-	kvm_mips_host_tlb_inv(vcpu, tlb->tlb_hi);
-
-	/* Invalidate the whole ASID on other CPUs */
-	cpu = smp_processor_id();
-	for_each_possible_cpu(i) {
-		if (i == cpu)
-			continue;
-		if (user)
-			vcpu->arch.guest_user_asid[i] = 0;
-		vcpu->arch.guest_kernel_asid[i] = 0;
-	}
-
-	preempt_enable();
-}
-
 /* Write Guest TLB Entry @ Index */
 enum emulation_result kvm_mips_emul_tlbwi(struct kvm_vcpu *vcpu)
 {
@@ -373,8 +332,8 @@ enum emulation_result kvm_mips_emul_tlbwi(struct kvm_vcpu *vcpu)
 
 	tlb = &vcpu->arch.guest_tlb[index];
 #if 1
-
-	kvm_mips_invalidate_guest_tlb(vcpu, tlb);
+	/* Probe the shadow host TLB for the entry being overwritten, if one matches, invalidate it */
+	kvm_mips_host_tlb_inv(vcpu, tlb->tlb_hi);
 #endif
 
 	tlb->tlb_mask = kvm_read_c0_guest_pagemask(cop0);
@@ -415,7 +374,8 @@ enum emulation_result kvm_mips_emul_tlbwr(struct kvm_vcpu *vcpu)
 	tlb = &vcpu->arch.guest_tlb[index];
 
 #if 1
-	kvm_mips_invalidate_guest_tlb(vcpu, tlb);
+	/* Probe the shadow host TLB for the entry being overwritten, if one matches, invalidate it */
+	kvm_mips_host_tlb_inv(vcpu, tlb->tlb_hi);
 #endif
 
 	tlb->tlb_mask = kvm_read_c0_guest_pagemask(cop0);
@@ -459,7 +419,6 @@ kvm_mips_emulate_CP0(uint32_t inst, uint32_t *opc, uint32_t cause,
 	int32_t rt, rd, copz, sel, co_bit, op;
 	uint32_t pc = vcpu->arch.pc;
 	unsigned long curr_pc;
-	int cpu, i;
 
 	/*
 	 * Update PC and hold onto current PC in case there is
@@ -579,16 +538,8 @@ kvm_mips_emulate_CP0(uint32_t inst, uint32_t *opc, uint32_t cause,
 					     ASID_MASK,
 					     vcpu->arch.gprs[rt] & ASID_MASK);
 
-					preempt_disable();
 					/* Blow away the shadow host TLBs */
 					kvm_mips_flush_host_tlb(1);
-					cpu = smp_processor_id();
-					for_each_possible_cpu(i)
-						if (i != cpu) {
-							vcpu->arch.guest_user_asid[i] = 0;
-							vcpu->arch.guest_kernel_asid[i] = 0;
-						}
-					preempt_enable();
 				}
 				kvm_write_c0_guest_entryhi(cop0,
 							   vcpu->arch.gprs[rt]);
-- 
2.10.2