linux/arch/mips/kvm/tlb.c
James Hogan 4cf74c9c83 KVM: MIPS/Emulate: Use lockless GVA helpers for cache emulation
Use the lockless GVA helpers to implement the reading of guest
instructions for emulation. This will allow it to handle asynchronous
TLB flushes when they are implemented.

This is a little more complicated than the other two cases (get_inst()
and dynamic translation) due to the need to emulate the appropriate
guest TLB exception when the address isn't present or isn't valid in the
guest TLB.

Since there are several protected cache ops that may need to be
performed safely, this is abstracted by kvm_mips_guest_cache_op() which
is passed a protected cache op function pointer and takes care of the
lockless operation and fault handling / retry if the op should fail,
taking advantage of the new errors which the protected cache ops can now
return. This allows the existing advance fault handling which relied on
host TLB lookups to be removed, along with the now unused
kvm_mips_host_tlb_lookup(),

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
2017-02-03 15:21:15 +00:00

216 lines
5.4 KiB
C

/*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*
* KVM/MIPS TLB handling, this file is part of the Linux host kernel so that
* TLB handlers run from KSEG0
*
* Copyright (C) 2012 MIPS Technologies, Inc. All rights reserved.
* Authors: Sanjay Lal <sanjayl@kymasys.com>
*/
#include <linux/sched.h>
#include <linux/smp.h>
#include <linux/mm.h>
#include <linux/delay.h>
#include <linux/export.h>
#include <linux/kvm_host.h>
#include <linux/srcu.h>
#include <asm/cpu.h>
#include <asm/bootinfo.h>
#include <asm/mmu_context.h>
#include <asm/pgtable.h>
#include <asm/cacheflush.h>
#include <asm/tlb.h>
#include <asm/tlbdebug.h>
#undef CONFIG_MIPS_MT
#include <asm/r4kcache.h>
#define CONFIG_MIPS_MT
#define KVM_GUEST_PC_TLB 0
#define KVM_GUEST_SP_TLB 1
static u32 kvm_mips_get_kernel_asid(struct kvm_vcpu *vcpu)
{
struct mm_struct *kern_mm = &vcpu->arch.guest_kernel_mm;
int cpu = smp_processor_id();
return cpu_asid(cpu, kern_mm);
}
static u32 kvm_mips_get_user_asid(struct kvm_vcpu *vcpu)
{
struct mm_struct *user_mm = &vcpu->arch.guest_user_mm;
int cpu = smp_processor_id();
return cpu_asid(cpu, user_mm);
}
/* Structure defining an tlb entry data set. */
void kvm_mips_dump_host_tlbs(void)
{
unsigned long flags;
local_irq_save(flags);
kvm_info("HOST TLBs:\n");
dump_tlb_regs();
pr_info("\n");
dump_tlb_all();
local_irq_restore(flags);
}
EXPORT_SYMBOL_GPL(kvm_mips_dump_host_tlbs);
void kvm_mips_dump_guest_tlbs(struct kvm_vcpu *vcpu)
{
struct mips_coproc *cop0 = vcpu->arch.cop0;
struct kvm_mips_tlb tlb;
int i;
kvm_info("Guest TLBs:\n");
kvm_info("Guest EntryHi: %#lx\n", kvm_read_c0_guest_entryhi(cop0));
for (i = 0; i < KVM_MIPS_GUEST_TLB_SIZE; i++) {
tlb = vcpu->arch.guest_tlb[i];
kvm_info("TLB%c%3d Hi 0x%08lx ",
(tlb.tlb_lo[0] | tlb.tlb_lo[1]) & ENTRYLO_V
? ' ' : '*',
i, tlb.tlb_hi);
kvm_info("Lo0=0x%09llx %c%c attr %lx ",
(u64) mips3_tlbpfn_to_paddr(tlb.tlb_lo[0]),
(tlb.tlb_lo[0] & ENTRYLO_D) ? 'D' : ' ',
(tlb.tlb_lo[0] & ENTRYLO_G) ? 'G' : ' ',
(tlb.tlb_lo[0] & ENTRYLO_C) >> ENTRYLO_C_SHIFT);
kvm_info("Lo1=0x%09llx %c%c attr %lx sz=%lx\n",
(u64) mips3_tlbpfn_to_paddr(tlb.tlb_lo[1]),
(tlb.tlb_lo[1] & ENTRYLO_D) ? 'D' : ' ',
(tlb.tlb_lo[1] & ENTRYLO_G) ? 'G' : ' ',
(tlb.tlb_lo[1] & ENTRYLO_C) >> ENTRYLO_C_SHIFT,
tlb.tlb_mask);
}
}
EXPORT_SYMBOL_GPL(kvm_mips_dump_guest_tlbs);
int kvm_mips_guest_tlb_lookup(struct kvm_vcpu *vcpu, unsigned long entryhi)
{
int i;
int index = -1;
struct kvm_mips_tlb *tlb = vcpu->arch.guest_tlb;
for (i = 0; i < KVM_MIPS_GUEST_TLB_SIZE; i++) {
if (TLB_HI_VPN2_HIT(tlb[i], entryhi) &&
TLB_HI_ASID_HIT(tlb[i], entryhi)) {
index = i;
break;
}
}
kvm_debug("%s: entryhi: %#lx, index: %d lo0: %#lx, lo1: %#lx\n",
__func__, entryhi, index, tlb[i].tlb_lo[0], tlb[i].tlb_lo[1]);
return index;
}
EXPORT_SYMBOL_GPL(kvm_mips_guest_tlb_lookup);
static int _kvm_mips_host_tlb_inv(unsigned long entryhi)
{
int idx;
write_c0_entryhi(entryhi);
mtc0_tlbw_hazard();
tlb_probe();
tlb_probe_hazard();
idx = read_c0_index();
if (idx >= current_cpu_data.tlbsize)
BUG();
if (idx >= 0) {
write_c0_entryhi(UNIQUE_ENTRYHI(idx));
write_c0_entrylo0(0);
write_c0_entrylo1(0);
mtc0_tlbw_hazard();
tlb_write_indexed();
tlbw_use_hazard();
}
return idx;
}
int kvm_mips_host_tlb_inv(struct kvm_vcpu *vcpu, unsigned long va,
bool user, bool kernel)
{
int idx_user, idx_kernel;
unsigned long flags, old_entryhi;
local_irq_save(flags);
old_entryhi = read_c0_entryhi();
if (user)
idx_user = _kvm_mips_host_tlb_inv((va & VPN2_MASK) |
kvm_mips_get_user_asid(vcpu));
if (kernel)
idx_kernel = _kvm_mips_host_tlb_inv((va & VPN2_MASK) |
kvm_mips_get_kernel_asid(vcpu));
write_c0_entryhi(old_entryhi);
mtc0_tlbw_hazard();
local_irq_restore(flags);
if (user && idx_user >= 0)
kvm_debug("%s: Invalidated guest user entryhi %#lx @ idx %d\n",
__func__, (va & VPN2_MASK) |
kvm_mips_get_user_asid(vcpu), idx_user);
if (kernel && idx_kernel >= 0)
kvm_debug("%s: Invalidated guest kernel entryhi %#lx @ idx %d\n",
__func__, (va & VPN2_MASK) |
kvm_mips_get_kernel_asid(vcpu), idx_kernel);
return 0;
}
EXPORT_SYMBOL_GPL(kvm_mips_host_tlb_inv);
/**
* kvm_mips_suspend_mm() - Suspend the active mm.
* @cpu The CPU we're running on.
*
* Suspend the active_mm, ready for a switch to a KVM guest virtual address
* space. This is left active for the duration of guest context, including time
* with interrupts enabled, so we need to be careful not to confuse e.g. cache
* management IPIs.
*
* kvm_mips_resume_mm() should be called before context switching to a different
* process so we don't need to worry about reference counting.
*
* This needs to be in static kernel code to avoid exporting init_mm.
*/
void kvm_mips_suspend_mm(int cpu)
{
cpumask_clear_cpu(cpu, mm_cpumask(current->active_mm));
current->active_mm = &init_mm;
}
EXPORT_SYMBOL_GPL(kvm_mips_suspend_mm);
/**
* kvm_mips_resume_mm() - Resume the current process mm.
* @cpu The CPU we're running on.
*
* Resume the mm of the current process, after a switch back from a KVM guest
* virtual address space (see kvm_mips_suspend_mm()).
*/
void kvm_mips_resume_mm(int cpu)
{
cpumask_set_cpu(cpu, mm_cpumask(current->mm));
current->active_mm = current->mm;
}
EXPORT_SYMBOL_GPL(kvm_mips_resume_mm);