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MIPS: KVM: remove shadow_tlb code

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The kvm_mips_init_shadow_tlb() function is called from
kvm_arch_vcpu_init() and initialises entries 0 to
current_cpu_data.tlbsize-1 of the virtual cpu's shadow_tlb[64] array.

However newer cores with FTLBs can have a tlbsize > 64, for example the
ProAptiv I'm testing on has a total tlbsize of 576. This causes
kvm_mips_init_shadow_tlb() to overflow the shadow_tlb[64] array and
overwrite the comparecount_timer among other things, causing a lock up
when starting a KVM guest.

Aside from kvm_mips_init_shadow_tlb() which only initialises it, the
shadow_tlb[64] array is only actually used by the following functions:
 - kvm_shadow_tlb_put() & kvm_shadow_tlb_load()
     These are never called. The only call sites are #if 0'd out.
 - kvm_mips_dump_shadow_tlbs()
     This is never called.

It was originally added for trap & emulate, but turned out to be
unnecessary so it was disabled.

So instead of fixing the shadow_tlb initialisation code, lets just
remove the shadow_tlb[64] array and the above functions entirely. The
only functional change here is the removal of broken shadow_tlb
initialisation. The rest just deletes dead code.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: Gleb Natapov <gleb@redhat.com>
Cc: kvm@vger.kernel.org
Cc: Sanjay Lal <sanjayl@kymasys.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: John Crispin <blogic@openwrt.org>
Patchwork: http://patchwork.linux-mips.org/patch/6384/
This commit is contained in:
James Hogan 2014-01-17 12:01:31 +00:00 committed by Ralf Baechle
parent e36059e508
commit 08596b0a75
3 changed files with 0 additions and 138 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

7
arch/mips/include/asm/kvm_host.h
View file

@ -391,9 +391,6 @@ struct kvm_vcpu_arch {
uint32_t guest_kernel_asid[NR_CPUS];
struct mm_struct guest_kernel_mm, guest_user_mm;
struct kvm_mips_tlb shadow_tlb[NR_CPUS][KVM_MIPS_GUEST_TLB_SIZE];
struct hrtimer comparecount_timer;
int last_sched_cpu;
@ -529,7 +526,6 @@ extern enum emulation_result kvm_mips_handle_tlbmod(unsigned long cause,
extern void kvm_mips_dump_host_tlbs(void);
extern void kvm_mips_dump_guest_tlbs(struct kvm_vcpu *vcpu);
extern void kvm_mips_dump_shadow_tlbs(struct kvm_vcpu *vcpu);
extern void kvm_mips_flush_host_tlb(int skip_kseg0);
extern int kvm_mips_host_tlb_inv(struct kvm_vcpu *vcpu, unsigned long entryhi);
extern int kvm_mips_host_tlb_inv_index(struct kvm_vcpu *vcpu, int index);
@ -541,10 +537,7 @@ extern unsigned long kvm_mips_translate_guest_kseg0_to_hpa(struct kvm_vcpu *vcpu
unsigned long gva);
extern void kvm_get_new_mmu_context(struct mm_struct *mm, unsigned long cpu,
struct kvm_vcpu *vcpu);
extern void kvm_shadow_tlb_put(struct kvm_vcpu *vcpu);
extern void kvm_shadow_tlb_load(struct kvm_vcpu *vcpu);
extern void kvm_local_flush_tlb_all(void);
extern void kvm_mips_init_shadow_tlb(struct kvm_vcpu *vcpu);
extern void kvm_mips_alloc_new_mmu_context(struct kvm_vcpu *vcpu);
extern void kvm_mips_vcpu_load(struct kvm_vcpu *vcpu, int cpu);
extern void kvm_mips_vcpu_put(struct kvm_vcpu *vcpu);

1
arch/mips/kvm/kvm_mips.c
View file

@ -1001,7 +1001,6 @@ int kvm_arch_vcpu_init(struct kvm_vcpu *vcpu)
hrtimer_init(&vcpu->arch.comparecount_timer, CLOCK_MONOTONIC,
HRTIMER_MODE_REL);
vcpu->arch.comparecount_timer.function = kvm_mips_comparecount_wakeup;
kvm_mips_init_shadow_tlb(vcpu);
return 0;
}

130
arch/mips/kvm/kvm_tlb.c
View file

@ -145,30 +145,6 @@ void kvm_mips_dump_guest_tlbs(struct kvm_vcpu *vcpu)
}
}
void kvm_mips_dump_shadow_tlbs(struct kvm_vcpu *vcpu)
{
int i;
volatile struct kvm_mips_tlb tlb;
printk("Shadow TLBs:\n");
for (i = 0; i < KVM_MIPS_GUEST_TLB_SIZE; i++) {
tlb = vcpu->arch.shadow_tlb[smp_processor_id()][i];
printk("TLB%c%3d Hi 0x%08lx ",
(tlb.tlb_lo0 | tlb.tlb_lo1) & MIPS3_PG_V ? ' ' : '*',
i, tlb.tlb_hi);
printk("Lo0=0x%09" PRIx64 " %c%c attr %lx ",
(uint64_t) mips3_tlbpfn_to_paddr(tlb.tlb_lo0),
(tlb.tlb_lo0 & MIPS3_PG_D) ? 'D' : ' ',
(tlb.tlb_lo0 & MIPS3_PG_G) ? 'G' : ' ',
(tlb.tlb_lo0 >> 3) & 7);
printk("Lo1=0x%09" PRIx64 " %c%c attr %lx sz=%lx\n",
(uint64_t) mips3_tlbpfn_to_paddr(tlb.tlb_lo1),
(tlb.tlb_lo1 & MIPS3_PG_D) ? 'D' : ' ',
(tlb.tlb_lo1 & MIPS3_PG_G) ? 'G' : ' ',
(tlb.tlb_lo1 >> 3) & 7, tlb.tlb_mask);
}
}
static int kvm_mips_map_page(struct kvm *kvm, gfn_t gfn)
{
int srcu_idx, err = 0;
@ -655,70 +631,6 @@ kvm_get_new_mmu_context(struct mm_struct *mm, unsigned long cpu,
cpu_context(cpu, mm) = asid_cache(cpu) = asid;
}
void kvm_shadow_tlb_put(struct kvm_vcpu *vcpu)
{
unsigned long flags;
unsigned long old_entryhi;
unsigned long old_pagemask;
int entry = 0;
int cpu = smp_processor_id();
local_irq_save(flags);
old_entryhi = read_c0_entryhi();
old_pagemask = read_c0_pagemask();
for (entry = 0; entry < current_cpu_data.tlbsize; entry++) {
write_c0_index(entry);
mtc0_tlbw_hazard();
tlb_read();
tlbw_use_hazard();
vcpu->arch.shadow_tlb[cpu][entry].tlb_hi = read_c0_entryhi();
vcpu->arch.shadow_tlb[cpu][entry].tlb_lo0 = read_c0_entrylo0();
vcpu->arch.shadow_tlb[cpu][entry].tlb_lo1 = read_c0_entrylo1();
vcpu->arch.shadow_tlb[cpu][entry].tlb_mask = read_c0_pagemask();
}
write_c0_entryhi(old_entryhi);
write_c0_pagemask(old_pagemask);
mtc0_tlbw_hazard();
local_irq_restore(flags);
}
void kvm_shadow_tlb_load(struct kvm_vcpu *vcpu)
{
unsigned long flags;
unsigned long old_ctx;
int entry;
int cpu = smp_processor_id();
local_irq_save(flags);
old_ctx = read_c0_entryhi();
for (entry = 0; entry < current_cpu_data.tlbsize; entry++) {
write_c0_entryhi(vcpu->arch.shadow_tlb[cpu][entry].tlb_hi);
mtc0_tlbw_hazard();
write_c0_entrylo0(vcpu->arch.shadow_tlb[cpu][entry].tlb_lo0);
write_c0_entrylo1(vcpu->arch.shadow_tlb[cpu][entry].tlb_lo1);
write_c0_index(entry);
mtc0_tlbw_hazard();
tlb_write_indexed();
tlbw_use_hazard();
}
tlbw_use_hazard();
write_c0_entryhi(old_ctx);
mtc0_tlbw_hazard();
local_irq_restore(flags);
}
void kvm_local_flush_tlb_all(void)
{
unsigned long flags;
@ -747,30 +659,6 @@ void kvm_local_flush_tlb_all(void)
local_irq_restore(flags);
}
void kvm_mips_init_shadow_tlb(struct kvm_vcpu *vcpu)
{
int cpu, entry;
for_each_possible_cpu(cpu) {
for (entry = 0; entry < current_cpu_data.tlbsize; entry++) {
vcpu->arch.shadow_tlb[cpu][entry].tlb_hi =
UNIQUE_ENTRYHI(entry);
vcpu->arch.shadow_tlb[cpu][entry].tlb_lo0 = 0x0;
vcpu->arch.shadow_tlb[cpu][entry].tlb_lo1 = 0x0;
vcpu->arch.shadow_tlb[cpu][entry].tlb_mask =
read_c0_pagemask();
#ifdef DEBUG
kvm_debug
("shadow_tlb[%d][%d]: tlb_hi: %#lx, lo0: %#lx, lo1: %#lx\n",
cpu, entry,
vcpu->arch.shadow_tlb[cpu][entry].tlb_hi,
vcpu->arch.shadow_tlb[cpu][entry].tlb_lo0,
vcpu->arch.shadow_tlb[cpu][entry].tlb_lo1);
#endif
}
}
}
/* Restore ASID once we are scheduled back after preemption */
void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
{
@ -808,14 +696,6 @@ void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
vcpu->arch.last_sched_cpu, cpu, vcpu->vcpu_id);
}
/* Only reload shadow host TLB if new ASIDs haven't been allocated */
#if 0
if ((atomic_read(&kvm_mips_instance) > 1) && !newasid) {
kvm_mips_flush_host_tlb(0);
kvm_shadow_tlb_load(vcpu);
}
#endif
if (!newasid) {
/* If we preempted while the guest was executing, then reload the pre-empted ASID */
if (current->flags & PF_VCPU) {
@ -861,12 +741,6 @@ void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu)
vcpu->arch.preempt_entryhi = read_c0_entryhi();
vcpu->arch.last_sched_cpu = cpu;
#if 0
if ((atomic_read(&kvm_mips_instance) > 1)) {
kvm_shadow_tlb_put(vcpu);
}
#endif
if (((cpu_context(cpu, current->mm) ^ asid_cache(cpu)) &
ASID_VERSION_MASK)) {
kvm_debug("%s: Dropping MMU Context: %#lx\n", __func__,
@ -928,10 +802,8 @@ uint32_t kvm_get_inst(uint32_t *opc, struct kvm_vcpu *vcpu)
}
EXPORT_SYMBOL(kvm_local_flush_tlb_all);
EXPORT_SYMBOL(kvm_shadow_tlb_put);
EXPORT_SYMBOL(kvm_mips_handle_mapped_seg_tlb_fault);
EXPORT_SYMBOL(kvm_mips_handle_commpage_tlb_fault);
EXPORT_SYMBOL(kvm_mips_init_shadow_tlb);
EXPORT_SYMBOL(kvm_mips_dump_host_tlbs);
EXPORT_SYMBOL(kvm_mips_handle_kseg0_tlb_fault);
EXPORT_SYMBOL(kvm_mips_host_tlb_lookup);
@ -939,8 +811,6 @@ EXPORT_SYMBOL(kvm_mips_flush_host_tlb);
EXPORT_SYMBOL(kvm_mips_guest_tlb_lookup);
EXPORT_SYMBOL(kvm_mips_host_tlb_inv);
EXPORT_SYMBOL(kvm_mips_translate_guest_kseg0_to_hpa);
EXPORT_SYMBOL(kvm_shadow_tlb_load);
EXPORT_SYMBOL(kvm_mips_dump_shadow_tlbs);
EXPORT_SYMBOL(kvm_mips_dump_guest_tlbs);
EXPORT_SYMBOL(kvm_get_inst);
EXPORT_SYMBOL(kvm_arch_vcpu_load);