mips/kvm/tlb.c

0001 /*
0002  * This file is subject to the terms and conditions of the GNU General Public
0003  * License.  See the file "COPYING" in the main directory of this archive
0004  * for more details.
0005  *
0006  * KVM/MIPS TLB handling, this file is part of the Linux host kernel so that
0007  * TLB handlers run from KSEG0
0008  *
0009  * Copyright (C) 2012  MIPS Technologies, Inc.  All rights reserved.
0010  * Authors: Sanjay Lal <sanjayl@kymasys.com>
0011  */
0012
0013 #include <linux/sched.h>
0014 #include <linux/smp.h>
0015 #include <linux/mm.h>
0016 #include <linux/delay.h>
0017 #include <linux/export.h>
0018 #include <linux/kvm_host.h>
0019 #include <linux/srcu.h>
0020
0021 #include <asm/cpu.h>
0022 #include <asm/bootinfo.h>
0023 #include <asm/mipsregs.h>
0024 #include <asm/mmu_context.h>
0025 #include <asm/cacheflush.h>
0026 #include <asm/tlb.h>
0027 #include <asm/tlbdebug.h>
0028
0029 #undef CONFIG_MIPS_MT
0030 #include <asm/r4kcache.h>
0031 #define CONFIG_MIPS_MT
0032
0033 unsigned long GUESTID_MASK;
0034 EXPORT_SYMBOL_GPL(GUESTID_MASK);
0035 unsigned long GUESTID_FIRST_VERSION;
0036 EXPORT_SYMBOL_GPL(GUESTID_FIRST_VERSION);
0037 unsigned long GUESTID_VERSION_MASK;
0038 EXPORT_SYMBOL_GPL(GUESTID_VERSION_MASK);
0039
0040 static u32 kvm_mips_get_root_asid(struct kvm_vcpu *vcpu)
0041 {
0042     struct mm_struct *gpa_mm = &vcpu->kvm->arch.gpa_mm;
0043
0044     if (cpu_has_guestid)
0045         return 0;
0046     else
0047         return cpu_asid(smp_processor_id(), gpa_mm);
0048 }
0049
0050 static int _kvm_mips_host_tlb_inv(unsigned long entryhi)
0051 {
0052     int idx;
0053
0054     write_c0_entryhi(entryhi);
0055     mtc0_tlbw_hazard();
0056
0057     tlb_probe();
0058     tlb_probe_hazard();
0059     idx = read_c0_index();
0060
0061     BUG_ON(idx >= current_cpu_data.tlbsize);
0062
0063     if (idx >= 0) {
0064         write_c0_entryhi(UNIQUE_ENTRYHI(idx));
0065         write_c0_entrylo0(0);
0066         write_c0_entrylo1(0);
0067         mtc0_tlbw_hazard();
0068
0069         tlb_write_indexed();
0070         tlbw_use_hazard();
0071     }
0072
0073     return idx;
0074 }
0075
0076 /* GuestID management */
0077
0078 /**
0079  * clear_root_gid() - Set GuestCtl1.RID for normal root operation.
0080  */
0081 static inline void clear_root_gid(void)
0082 {
0083     if (cpu_has_guestid) {
0084         clear_c0_guestctl1(MIPS_GCTL1_RID);
0085         mtc0_tlbw_hazard();
0086     }
0087 }
0088
0089 /**
0090  * set_root_gid_to_guest_gid() - Set GuestCtl1.RID to match GuestCtl1.ID.
0091  *
0092  * Sets the root GuestID to match the current guest GuestID, for TLB operation
0093  * on the GPA->RPA mappings in the root TLB.
0094  *
0095  * The caller must be sure to disable HTW while the root GID is set, and
0096  * possibly longer if TLB registers are modified.
0097  */
0098 static inline void set_root_gid_to_guest_gid(void)
0099 {
0100     unsigned int guestctl1;
0101
0102     if (cpu_has_guestid) {
0103         back_to_back_c0_hazard();
0104         guestctl1 = read_c0_guestctl1();
0105         guestctl1 = (guestctl1 & ~MIPS_GCTL1_RID) |
0106             ((guestctl1 & MIPS_GCTL1_ID) >> MIPS_GCTL1_ID_SHIFT)
0107                              << MIPS_GCTL1_RID_SHIFT;
0108         write_c0_guestctl1(guestctl1);
0109         mtc0_tlbw_hazard();
0110     }
0111 }
0112
0113 int kvm_vz_host_tlb_inv(struct kvm_vcpu *vcpu, unsigned long va)
0114 {
0115     int idx;
0116     unsigned long flags, old_entryhi;
0117
0118     local_irq_save(flags);
0119     htw_stop();
0120
0121     /* Set root GuestID for root probe and write of guest TLB entry */
0122     set_root_gid_to_guest_gid();
0123
0124     old_entryhi = read_c0_entryhi();
0125
0126     idx = _kvm_mips_host_tlb_inv((va & VPN2_MASK) |
0127                      kvm_mips_get_root_asid(vcpu));
0128
0129     write_c0_entryhi(old_entryhi);
0130     clear_root_gid();
0131     mtc0_tlbw_hazard();
0132
0133     htw_start();
0134     local_irq_restore(flags);
0135
0136     /*
0137      * We don't want to get reserved instruction exceptions for missing tlb
0138      * entries.
0139      */
0140     if (cpu_has_vtag_icache)
0141         flush_icache_all();
0142
0143     if (idx > 0)
0144         kvm_debug("%s: Invalidated root entryhi %#lx @ idx %d\n",
0145               __func__, (va & VPN2_MASK) |
0146                     kvm_mips_get_root_asid(vcpu), idx);
0147
0148     return 0;
0149 }
0150 EXPORT_SYMBOL_GPL(kvm_vz_host_tlb_inv);
0151
0152 /**
0153  * kvm_vz_guest_tlb_lookup() - Lookup a guest VZ TLB mapping.
0154  * @vcpu:   KVM VCPU pointer.
0155  * @gpa:    Guest virtual address in a TLB mapped guest segment.
0156  * @gpa:    Pointer to output guest physical address it maps to.
0157  *
0158  * Converts a guest virtual address in a guest TLB mapped segment to a guest
0159  * physical address, by probing the guest TLB.
0160  *
0161  * Returns: 0 if guest TLB mapping exists for @gva. *@gpa will have been
0162  *      written.
0163  *      -EFAULT if no guest TLB mapping exists for @gva. *@gpa may not
0164  *      have been written.
0165  */
0166 int kvm_vz_guest_tlb_lookup(struct kvm_vcpu *vcpu, unsigned long gva,
0167                 unsigned long *gpa)
0168 {
0169     unsigned long o_entryhi, o_entrylo[2], o_pagemask;
0170     unsigned int o_index;
0171     unsigned long entrylo[2], pagemask, pagemaskbit, pa;
0172     unsigned long flags;
0173     int index;
0174
0175     /* Probe the guest TLB for a mapping */
0176     local_irq_save(flags);
0177     /* Set root GuestID for root probe of guest TLB entry */
0178     htw_stop();
0179     set_root_gid_to_guest_gid();
0180
0181     o_entryhi = read_gc0_entryhi();
0182     o_index = read_gc0_index();
0183
0184     write_gc0_entryhi((o_entryhi & 0x3ff) | (gva & ~0xfffl));
0185     mtc0_tlbw_hazard();
0186     guest_tlb_probe();
0187     tlb_probe_hazard();
0188
0189     index = read_gc0_index();
0190     if (index < 0) {
0191         /* No match, fail */
0192         write_gc0_entryhi(o_entryhi);
0193         write_gc0_index(o_index);
0194
0195         clear_root_gid();
0196         htw_start();
0197         local_irq_restore(flags);
0198         return -EFAULT;
0199     }
0200
0201     /* Match! read the TLB entry */
0202     o_entrylo[0] = read_gc0_entrylo0();
0203     o_entrylo[1] = read_gc0_entrylo1();
0204     o_pagemask = read_gc0_pagemask();
0205
0206     mtc0_tlbr_hazard();
0207     guest_tlb_read();
0208     tlb_read_hazard();
0209
0210     entrylo[0] = read_gc0_entrylo0();
0211     entrylo[1] = read_gc0_entrylo1();
0212     pagemask = ~read_gc0_pagemask() & ~0x1fffl;
0213
0214     write_gc0_entryhi(o_entryhi);
0215     write_gc0_index(o_index);
0216     write_gc0_entrylo0(o_entrylo[0]);
0217     write_gc0_entrylo1(o_entrylo[1]);
0218     write_gc0_pagemask(o_pagemask);
0219
0220     clear_root_gid();
0221     htw_start();
0222     local_irq_restore(flags);
0223
0224     /* Select one of the EntryLo values and interpret the GPA */
0225     pagemaskbit = (pagemask ^ (pagemask & (pagemask - 1))) >> 1;
0226     pa = entrylo[!!(gva & pagemaskbit)];
0227
0228     /*
0229      * TLB entry may have become invalid since TLB probe if physical FTLB
0230      * entries are shared between threads (e.g. I6400).
0231      */
0232     if (!(pa & ENTRYLO_V))
0233         return -EFAULT;
0234
0235     /*
0236      * Note, this doesn't take guest MIPS32 XPA into account, where PFN is
0237      * split with XI/RI in the middle.
0238      */
0239     pa = (pa << 6) & ~0xfffl;
0240     pa |= gva & ~(pagemask | pagemaskbit);
0241
0242     *gpa = pa;
0243     return 0;
0244 }
0245 EXPORT_SYMBOL_GPL(kvm_vz_guest_tlb_lookup);
0246
0247 /**
0248  * kvm_vz_local_flush_roottlb_all_guests() - Flush all root TLB entries for
0249  * guests.
0250  *
0251  * Invalidate all entries in root tlb which are GPA mappings.
0252  */
0253 void kvm_vz_local_flush_roottlb_all_guests(void)
0254 {
0255     unsigned long flags;
0256     unsigned long old_entryhi, old_pagemask, old_guestctl1;
0257     int entry;
0258
0259     if (WARN_ON(!cpu_has_guestid))
0260         return;
0261
0262     local_irq_save(flags);
0263     htw_stop();
0264
0265     /* TLBR may clobber EntryHi.ASID, PageMask, and GuestCtl1.RID */
0266     old_entryhi = read_c0_entryhi();
0267     old_pagemask = read_c0_pagemask();
0268     old_guestctl1 = read_c0_guestctl1();
0269
0270     /*
0271      * Invalidate guest entries in root TLB while leaving root entries
0272      * intact when possible.
0273      */
0274     for (entry = 0; entry < current_cpu_data.tlbsize; entry++) {
0275         write_c0_index(entry);
0276         mtc0_tlbw_hazard();
0277         tlb_read();
0278         tlb_read_hazard();
0279
0280         /* Don't invalidate non-guest (RVA) mappings in the root TLB */
0281         if (!(read_c0_guestctl1() & MIPS_GCTL1_RID))
0282             continue;
0283
0284         /* Make sure all entries differ. */
0285         write_c0_entryhi(UNIQUE_ENTRYHI(entry));
0286         write_c0_entrylo0(0);
0287         write_c0_entrylo1(0);
0288         write_c0_guestctl1(0);
0289         mtc0_tlbw_hazard();
0290         tlb_write_indexed();
0291     }
0292
0293     write_c0_entryhi(old_entryhi);
0294     write_c0_pagemask(old_pagemask);
0295     write_c0_guestctl1(old_guestctl1);
0296     tlbw_use_hazard();
0297
0298     htw_start();
0299     local_irq_restore(flags);
0300 }
0301 EXPORT_SYMBOL_GPL(kvm_vz_local_flush_roottlb_all_guests);
0302
0303 /**
0304  * kvm_vz_local_flush_guesttlb_all() - Flush all guest TLB entries.
0305  *
0306  * Invalidate all entries in guest tlb irrespective of guestid.
0307  */
0308 void kvm_vz_local_flush_guesttlb_all(void)
0309 {
0310     unsigned long flags;
0311     unsigned long old_index;
0312     unsigned long old_entryhi;
0313     unsigned long old_entrylo[2];
0314     unsigned long old_pagemask;
0315     int entry;
0316     u64 cvmmemctl2 = 0;
0317
0318     local_irq_save(flags);
0319
0320     /* Preserve all clobbered guest registers */
0321     old_index = read_gc0_index();
0322     old_entryhi = read_gc0_entryhi();
0323     old_entrylo[0] = read_gc0_entrylo0();
0324     old_entrylo[1] = read_gc0_entrylo1();
0325     old_pagemask = read_gc0_pagemask();
0326
0327     switch (current_cpu_type()) {
0328     case CPU_CAVIUM_OCTEON3:
0329         /* Inhibit machine check due to multiple matching TLB entries */
0330         cvmmemctl2 = read_c0_cvmmemctl2();
0331         cvmmemctl2 |= CVMMEMCTL2_INHIBITTS;
0332         write_c0_cvmmemctl2(cvmmemctl2);
0333         break;
0334     }
0335
0336     /* Invalidate guest entries in guest TLB */
0337     write_gc0_entrylo0(0);
0338     write_gc0_entrylo1(0);
0339     write_gc0_pagemask(0);
0340     for (entry = 0; entry < current_cpu_data.guest.tlbsize; entry++) {
0341         /* Make sure all entries differ. */
0342         write_gc0_index(entry);
0343         write_gc0_entryhi(UNIQUE_GUEST_ENTRYHI(entry));
0344         mtc0_tlbw_hazard();
0345         guest_tlb_write_indexed();
0346     }
0347
0348     if (cvmmemctl2) {
0349         cvmmemctl2 &= ~CVMMEMCTL2_INHIBITTS;
0350         write_c0_cvmmemctl2(cvmmemctl2);
0351     }
0352
0353     write_gc0_index(old_index);
0354     write_gc0_entryhi(old_entryhi);
0355     write_gc0_entrylo0(old_entrylo[0]);
0356     write_gc0_entrylo1(old_entrylo[1]);
0357     write_gc0_pagemask(old_pagemask);
0358     tlbw_use_hazard();
0359
0360     local_irq_restore(flags);
0361 }
0362 EXPORT_SYMBOL_GPL(kvm_vz_local_flush_guesttlb_all);
0363
0364 /**
0365  * kvm_vz_save_guesttlb() - Save a range of guest TLB entries.
0366  * @buf:    Buffer to write TLB entries into.
0367  * @index:  Start index.
0368  * @count:  Number of entries to save.
0369  *
0370  * Save a range of guest TLB entries. The caller must ensure interrupts are
0371  * disabled.
0372  */
0373 void kvm_vz_save_guesttlb(struct kvm_mips_tlb *buf, unsigned int index,
0374               unsigned int count)
0375 {
0376     unsigned int end = index + count;
0377     unsigned long old_entryhi, old_entrylo0, old_entrylo1, old_pagemask;
0378     unsigned int guestctl1 = 0;
0379     int old_index, i;
0380
0381     /* Save registers we're about to clobber */
0382     old_index = read_gc0_index();
0383     old_entryhi = read_gc0_entryhi();
0384     old_entrylo0 = read_gc0_entrylo0();
0385     old_entrylo1 = read_gc0_entrylo1();
0386     old_pagemask = read_gc0_pagemask();
0387
0388     /* Set root GuestID for root probe */
0389     htw_stop();
0390     set_root_gid_to_guest_gid();
0391     if (cpu_has_guestid)
0392         guestctl1 = read_c0_guestctl1();
0393
0394     /* Read each entry from guest TLB */
0395     for (i = index; i < end; ++i, ++buf) {
0396         write_gc0_index(i);
0397
0398         mtc0_tlbr_hazard();
0399         guest_tlb_read();
0400         tlb_read_hazard();
0401
0402         if (cpu_has_guestid &&
0403             (read_c0_guestctl1() ^ guestctl1) & MIPS_GCTL1_RID) {
0404             /* Entry invalid or belongs to another guest */
0405             buf->tlb_hi = UNIQUE_GUEST_ENTRYHI(i);
0406             buf->tlb_lo[0] = 0;
0407             buf->tlb_lo[1] = 0;
0408             buf->tlb_mask = 0;
0409         } else {
0410             /* Entry belongs to the right guest */
0411             buf->tlb_hi = read_gc0_entryhi();
0412             buf->tlb_lo[0] = read_gc0_entrylo0();
0413             buf->tlb_lo[1] = read_gc0_entrylo1();
0414             buf->tlb_mask = read_gc0_pagemask();
0415         }
0416     }
0417
0418     /* Clear root GuestID again */
0419     clear_root_gid();
0420     htw_start();
0421
0422     /* Restore clobbered registers */
0423     write_gc0_index(old_index);
0424     write_gc0_entryhi(old_entryhi);
0425     write_gc0_entrylo0(old_entrylo0);
0426     write_gc0_entrylo1(old_entrylo1);
0427     write_gc0_pagemask(old_pagemask);
0428
0429     tlbw_use_hazard();
0430 }
0431 EXPORT_SYMBOL_GPL(kvm_vz_save_guesttlb);
0432
0433 /**
0434  * kvm_vz_load_guesttlb() - Save a range of guest TLB entries.
0435  * @buf:    Buffer to read TLB entries from.
0436  * @index:  Start index.
0437  * @count:  Number of entries to load.
0438  *
0439  * Load a range of guest TLB entries. The caller must ensure interrupts are
0440  * disabled.
0441  */
0442 void kvm_vz_load_guesttlb(const struct kvm_mips_tlb *buf, unsigned int index,
0443               unsigned int count)
0444 {
0445     unsigned int end = index + count;
0446     unsigned long old_entryhi, old_entrylo0, old_entrylo1, old_pagemask;
0447     int old_index, i;
0448
0449     /* Save registers we're about to clobber */
0450     old_index = read_gc0_index();
0451     old_entryhi = read_gc0_entryhi();
0452     old_entrylo0 = read_gc0_entrylo0();
0453     old_entrylo1 = read_gc0_entrylo1();
0454     old_pagemask = read_gc0_pagemask();
0455
0456     /* Set root GuestID for root probe */
0457     htw_stop();
0458     set_root_gid_to_guest_gid();
0459
0460     /* Write each entry to guest TLB */
0461     for (i = index; i < end; ++i, ++buf) {
0462         write_gc0_index(i);
0463         write_gc0_entryhi(buf->tlb_hi);
0464         write_gc0_entrylo0(buf->tlb_lo[0]);
0465         write_gc0_entrylo1(buf->tlb_lo[1]);
0466         write_gc0_pagemask(buf->tlb_mask);
0467
0468         mtc0_tlbw_hazard();
0469         guest_tlb_write_indexed();
0470     }
0471
0472     /* Clear root GuestID again */
0473     clear_root_gid();
0474     htw_start();
0475
0476     /* Restore clobbered registers */
0477     write_gc0_index(old_index);
0478     write_gc0_entryhi(old_entryhi);
0479     write_gc0_entrylo0(old_entrylo0);
0480     write_gc0_entrylo1(old_entrylo1);
0481     write_gc0_pagemask(old_pagemask);
0482
0483     tlbw_use_hazard();
0484 }
0485 EXPORT_SYMBOL_GPL(kvm_vz_load_guesttlb);
0486
0487 #ifdef CONFIG_CPU_LOONGSON64
0488 void kvm_loongson_clear_guest_vtlb(void)
0489 {
0490     int idx = read_gc0_index();
0491
0492     /* Set root GuestID for root probe and write of guest TLB entry */
0493     set_root_gid_to_guest_gid();
0494
0495     write_gc0_index(0);
0496     guest_tlbinvf();
0497     write_gc0_index(idx);
0498
0499     clear_root_gid();
0500     set_c0_diag(LOONGSON_DIAG_ITLB | LOONGSON_DIAG_DTLB);
0501 }
0502 EXPORT_SYMBOL_GPL(kvm_loongson_clear_guest_vtlb);
0503
0504 void kvm_loongson_clear_guest_ftlb(void)
0505 {
0506     int i;
0507     int idx = read_gc0_index();
0508
0509     /* Set root GuestID for root probe and write of guest TLB entry */
0510     set_root_gid_to_guest_gid();
0511
0512     for (i = current_cpu_data.tlbsizevtlb;
0513          i < (current_cpu_data.tlbsizevtlb +
0514              current_cpu_data.tlbsizeftlbsets);
0515          i++) {
0516         write_gc0_index(i);
0517         guest_tlbinvf();
0518     }
0519     write_gc0_index(idx);
0520
0521     clear_root_gid();
0522     set_c0_diag(LOONGSON_DIAG_ITLB | LOONGSON_DIAG_DTLB);
0523 }
0524 EXPORT_SYMBOL_GPL(kvm_loongson_clear_guest_ftlb);
0525 #endif