cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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tlb.c (13078B)


      1/*
      2 * This file is subject to the terms and conditions of the GNU General Public
      3 * License.  See the file "COPYING" in the main directory of this archive
      4 * for more details.
      5 *
      6 * KVM/MIPS TLB handling, this file is part of the Linux host kernel so that
      7 * TLB handlers run from KSEG0
      8 *
      9 * Copyright (C) 2012  MIPS Technologies, Inc.  All rights reserved.
     10 * Authors: Sanjay Lal <sanjayl@kymasys.com>
     11 */
     12
     13#include <linux/sched.h>
     14#include <linux/smp.h>
     15#include <linux/mm.h>
     16#include <linux/delay.h>
     17#include <linux/export.h>
     18#include <linux/kvm_host.h>
     19#include <linux/srcu.h>
     20
     21#include <asm/cpu.h>
     22#include <asm/bootinfo.h>
     23#include <asm/mipsregs.h>
     24#include <asm/mmu_context.h>
     25#include <asm/cacheflush.h>
     26#include <asm/tlb.h>
     27#include <asm/tlbdebug.h>
     28
     29#undef CONFIG_MIPS_MT
     30#include <asm/r4kcache.h>
     31#define CONFIG_MIPS_MT
     32
     33unsigned long GUESTID_MASK;
     34EXPORT_SYMBOL_GPL(GUESTID_MASK);
     35unsigned long GUESTID_FIRST_VERSION;
     36EXPORT_SYMBOL_GPL(GUESTID_FIRST_VERSION);
     37unsigned long GUESTID_VERSION_MASK;
     38EXPORT_SYMBOL_GPL(GUESTID_VERSION_MASK);
     39
     40static u32 kvm_mips_get_root_asid(struct kvm_vcpu *vcpu)
     41{
     42	struct mm_struct *gpa_mm = &vcpu->kvm->arch.gpa_mm;
     43
     44	if (cpu_has_guestid)
     45		return 0;
     46	else
     47		return cpu_asid(smp_processor_id(), gpa_mm);
     48}
     49
     50static int _kvm_mips_host_tlb_inv(unsigned long entryhi)
     51{
     52	int idx;
     53
     54	write_c0_entryhi(entryhi);
     55	mtc0_tlbw_hazard();
     56
     57	tlb_probe();
     58	tlb_probe_hazard();
     59	idx = read_c0_index();
     60
     61	BUG_ON(idx >= current_cpu_data.tlbsize);
     62
     63	if (idx >= 0) {
     64		write_c0_entryhi(UNIQUE_ENTRYHI(idx));
     65		write_c0_entrylo0(0);
     66		write_c0_entrylo1(0);
     67		mtc0_tlbw_hazard();
     68
     69		tlb_write_indexed();
     70		tlbw_use_hazard();
     71	}
     72
     73	return idx;
     74}
     75
     76/* GuestID management */
     77
     78/**
     79 * clear_root_gid() - Set GuestCtl1.RID for normal root operation.
     80 */
     81static inline void clear_root_gid(void)
     82{
     83	if (cpu_has_guestid) {
     84		clear_c0_guestctl1(MIPS_GCTL1_RID);
     85		mtc0_tlbw_hazard();
     86	}
     87}
     88
     89/**
     90 * set_root_gid_to_guest_gid() - Set GuestCtl1.RID to match GuestCtl1.ID.
     91 *
     92 * Sets the root GuestID to match the current guest GuestID, for TLB operation
     93 * on the GPA->RPA mappings in the root TLB.
     94 *
     95 * The caller must be sure to disable HTW while the root GID is set, and
     96 * possibly longer if TLB registers are modified.
     97 */
     98static inline void set_root_gid_to_guest_gid(void)
     99{
    100	unsigned int guestctl1;
    101
    102	if (cpu_has_guestid) {
    103		back_to_back_c0_hazard();
    104		guestctl1 = read_c0_guestctl1();
    105		guestctl1 = (guestctl1 & ~MIPS_GCTL1_RID) |
    106			((guestctl1 & MIPS_GCTL1_ID) >> MIPS_GCTL1_ID_SHIFT)
    107						     << MIPS_GCTL1_RID_SHIFT;
    108		write_c0_guestctl1(guestctl1);
    109		mtc0_tlbw_hazard();
    110	}
    111}
    112
    113int kvm_vz_host_tlb_inv(struct kvm_vcpu *vcpu, unsigned long va)
    114{
    115	int idx;
    116	unsigned long flags, old_entryhi;
    117
    118	local_irq_save(flags);
    119	htw_stop();
    120
    121	/* Set root GuestID for root probe and write of guest TLB entry */
    122	set_root_gid_to_guest_gid();
    123
    124	old_entryhi = read_c0_entryhi();
    125
    126	idx = _kvm_mips_host_tlb_inv((va & VPN2_MASK) |
    127				     kvm_mips_get_root_asid(vcpu));
    128
    129	write_c0_entryhi(old_entryhi);
    130	clear_root_gid();
    131	mtc0_tlbw_hazard();
    132
    133	htw_start();
    134	local_irq_restore(flags);
    135
    136	/*
    137	 * We don't want to get reserved instruction exceptions for missing tlb
    138	 * entries.
    139	 */
    140	if (cpu_has_vtag_icache)
    141		flush_icache_all();
    142
    143	if (idx > 0)
    144		kvm_debug("%s: Invalidated root entryhi %#lx @ idx %d\n",
    145			  __func__, (va & VPN2_MASK) |
    146				    kvm_mips_get_root_asid(vcpu), idx);
    147
    148	return 0;
    149}
    150EXPORT_SYMBOL_GPL(kvm_vz_host_tlb_inv);
    151
    152/**
    153 * kvm_vz_guest_tlb_lookup() - Lookup a guest VZ TLB mapping.
    154 * @vcpu:	KVM VCPU pointer.
    155 * @gpa:	Guest virtual address in a TLB mapped guest segment.
    156 * @gpa:	Pointer to output guest physical address it maps to.
    157 *
    158 * Converts a guest virtual address in a guest TLB mapped segment to a guest
    159 * physical address, by probing the guest TLB.
    160 *
    161 * Returns:	0 if guest TLB mapping exists for @gva. *@gpa will have been
    162 *		written.
    163 *		-EFAULT if no guest TLB mapping exists for @gva. *@gpa may not
    164 *		have been written.
    165 */
    166int kvm_vz_guest_tlb_lookup(struct kvm_vcpu *vcpu, unsigned long gva,
    167			    unsigned long *gpa)
    168{
    169	unsigned long o_entryhi, o_entrylo[2], o_pagemask;
    170	unsigned int o_index;
    171	unsigned long entrylo[2], pagemask, pagemaskbit, pa;
    172	unsigned long flags;
    173	int index;
    174
    175	/* Probe the guest TLB for a mapping */
    176	local_irq_save(flags);
    177	/* Set root GuestID for root probe of guest TLB entry */
    178	htw_stop();
    179	set_root_gid_to_guest_gid();
    180
    181	o_entryhi = read_gc0_entryhi();
    182	o_index = read_gc0_index();
    183
    184	write_gc0_entryhi((o_entryhi & 0x3ff) | (gva & ~0xfffl));
    185	mtc0_tlbw_hazard();
    186	guest_tlb_probe();
    187	tlb_probe_hazard();
    188
    189	index = read_gc0_index();
    190	if (index < 0) {
    191		/* No match, fail */
    192		write_gc0_entryhi(o_entryhi);
    193		write_gc0_index(o_index);
    194
    195		clear_root_gid();
    196		htw_start();
    197		local_irq_restore(flags);
    198		return -EFAULT;
    199	}
    200
    201	/* Match! read the TLB entry */
    202	o_entrylo[0] = read_gc0_entrylo0();
    203	o_entrylo[1] = read_gc0_entrylo1();
    204	o_pagemask = read_gc0_pagemask();
    205
    206	mtc0_tlbr_hazard();
    207	guest_tlb_read();
    208	tlb_read_hazard();
    209
    210	entrylo[0] = read_gc0_entrylo0();
    211	entrylo[1] = read_gc0_entrylo1();
    212	pagemask = ~read_gc0_pagemask() & ~0x1fffl;
    213
    214	write_gc0_entryhi(o_entryhi);
    215	write_gc0_index(o_index);
    216	write_gc0_entrylo0(o_entrylo[0]);
    217	write_gc0_entrylo1(o_entrylo[1]);
    218	write_gc0_pagemask(o_pagemask);
    219
    220	clear_root_gid();
    221	htw_start();
    222	local_irq_restore(flags);
    223
    224	/* Select one of the EntryLo values and interpret the GPA */
    225	pagemaskbit = (pagemask ^ (pagemask & (pagemask - 1))) >> 1;
    226	pa = entrylo[!!(gva & pagemaskbit)];
    227
    228	/*
    229	 * TLB entry may have become invalid since TLB probe if physical FTLB
    230	 * entries are shared between threads (e.g. I6400).
    231	 */
    232	if (!(pa & ENTRYLO_V))
    233		return -EFAULT;
    234
    235	/*
    236	 * Note, this doesn't take guest MIPS32 XPA into account, where PFN is
    237	 * split with XI/RI in the middle.
    238	 */
    239	pa = (pa << 6) & ~0xfffl;
    240	pa |= gva & ~(pagemask | pagemaskbit);
    241
    242	*gpa = pa;
    243	return 0;
    244}
    245EXPORT_SYMBOL_GPL(kvm_vz_guest_tlb_lookup);
    246
    247/**
    248 * kvm_vz_local_flush_roottlb_all_guests() - Flush all root TLB entries for
    249 * guests.
    250 *
    251 * Invalidate all entries in root tlb which are GPA mappings.
    252 */
    253void kvm_vz_local_flush_roottlb_all_guests(void)
    254{
    255	unsigned long flags;
    256	unsigned long old_entryhi, old_pagemask, old_guestctl1;
    257	int entry;
    258
    259	if (WARN_ON(!cpu_has_guestid))
    260		return;
    261
    262	local_irq_save(flags);
    263	htw_stop();
    264
    265	/* TLBR may clobber EntryHi.ASID, PageMask, and GuestCtl1.RID */
    266	old_entryhi = read_c0_entryhi();
    267	old_pagemask = read_c0_pagemask();
    268	old_guestctl1 = read_c0_guestctl1();
    269
    270	/*
    271	 * Invalidate guest entries in root TLB while leaving root entries
    272	 * intact when possible.
    273	 */
    274	for (entry = 0; entry < current_cpu_data.tlbsize; entry++) {
    275		write_c0_index(entry);
    276		mtc0_tlbw_hazard();
    277		tlb_read();
    278		tlb_read_hazard();
    279
    280		/* Don't invalidate non-guest (RVA) mappings in the root TLB */
    281		if (!(read_c0_guestctl1() & MIPS_GCTL1_RID))
    282			continue;
    283
    284		/* Make sure all entries differ. */
    285		write_c0_entryhi(UNIQUE_ENTRYHI(entry));
    286		write_c0_entrylo0(0);
    287		write_c0_entrylo1(0);
    288		write_c0_guestctl1(0);
    289		mtc0_tlbw_hazard();
    290		tlb_write_indexed();
    291	}
    292
    293	write_c0_entryhi(old_entryhi);
    294	write_c0_pagemask(old_pagemask);
    295	write_c0_guestctl1(old_guestctl1);
    296	tlbw_use_hazard();
    297
    298	htw_start();
    299	local_irq_restore(flags);
    300}
    301EXPORT_SYMBOL_GPL(kvm_vz_local_flush_roottlb_all_guests);
    302
    303/**
    304 * kvm_vz_local_flush_guesttlb_all() - Flush all guest TLB entries.
    305 *
    306 * Invalidate all entries in guest tlb irrespective of guestid.
    307 */
    308void kvm_vz_local_flush_guesttlb_all(void)
    309{
    310	unsigned long flags;
    311	unsigned long old_index;
    312	unsigned long old_entryhi;
    313	unsigned long old_entrylo[2];
    314	unsigned long old_pagemask;
    315	int entry;
    316	u64 cvmmemctl2 = 0;
    317
    318	local_irq_save(flags);
    319
    320	/* Preserve all clobbered guest registers */
    321	old_index = read_gc0_index();
    322	old_entryhi = read_gc0_entryhi();
    323	old_entrylo[0] = read_gc0_entrylo0();
    324	old_entrylo[1] = read_gc0_entrylo1();
    325	old_pagemask = read_gc0_pagemask();
    326
    327	switch (current_cpu_type()) {
    328	case CPU_CAVIUM_OCTEON3:
    329		/* Inhibit machine check due to multiple matching TLB entries */
    330		cvmmemctl2 = read_c0_cvmmemctl2();
    331		cvmmemctl2 |= CVMMEMCTL2_INHIBITTS;
    332		write_c0_cvmmemctl2(cvmmemctl2);
    333		break;
    334	}
    335
    336	/* Invalidate guest entries in guest TLB */
    337	write_gc0_entrylo0(0);
    338	write_gc0_entrylo1(0);
    339	write_gc0_pagemask(0);
    340	for (entry = 0; entry < current_cpu_data.guest.tlbsize; entry++) {
    341		/* Make sure all entries differ. */
    342		write_gc0_index(entry);
    343		write_gc0_entryhi(UNIQUE_GUEST_ENTRYHI(entry));
    344		mtc0_tlbw_hazard();
    345		guest_tlb_write_indexed();
    346	}
    347
    348	if (cvmmemctl2) {
    349		cvmmemctl2 &= ~CVMMEMCTL2_INHIBITTS;
    350		write_c0_cvmmemctl2(cvmmemctl2);
    351	}
    352
    353	write_gc0_index(old_index);
    354	write_gc0_entryhi(old_entryhi);
    355	write_gc0_entrylo0(old_entrylo[0]);
    356	write_gc0_entrylo1(old_entrylo[1]);
    357	write_gc0_pagemask(old_pagemask);
    358	tlbw_use_hazard();
    359
    360	local_irq_restore(flags);
    361}
    362EXPORT_SYMBOL_GPL(kvm_vz_local_flush_guesttlb_all);
    363
    364/**
    365 * kvm_vz_save_guesttlb() - Save a range of guest TLB entries.
    366 * @buf:	Buffer to write TLB entries into.
    367 * @index:	Start index.
    368 * @count:	Number of entries to save.
    369 *
    370 * Save a range of guest TLB entries. The caller must ensure interrupts are
    371 * disabled.
    372 */
    373void kvm_vz_save_guesttlb(struct kvm_mips_tlb *buf, unsigned int index,
    374			  unsigned int count)
    375{
    376	unsigned int end = index + count;
    377	unsigned long old_entryhi, old_entrylo0, old_entrylo1, old_pagemask;
    378	unsigned int guestctl1 = 0;
    379	int old_index, i;
    380
    381	/* Save registers we're about to clobber */
    382	old_index = read_gc0_index();
    383	old_entryhi = read_gc0_entryhi();
    384	old_entrylo0 = read_gc0_entrylo0();
    385	old_entrylo1 = read_gc0_entrylo1();
    386	old_pagemask = read_gc0_pagemask();
    387
    388	/* Set root GuestID for root probe */
    389	htw_stop();
    390	set_root_gid_to_guest_gid();
    391	if (cpu_has_guestid)
    392		guestctl1 = read_c0_guestctl1();
    393
    394	/* Read each entry from guest TLB */
    395	for (i = index; i < end; ++i, ++buf) {
    396		write_gc0_index(i);
    397
    398		mtc0_tlbr_hazard();
    399		guest_tlb_read();
    400		tlb_read_hazard();
    401
    402		if (cpu_has_guestid &&
    403		    (read_c0_guestctl1() ^ guestctl1) & MIPS_GCTL1_RID) {
    404			/* Entry invalid or belongs to another guest */
    405			buf->tlb_hi = UNIQUE_GUEST_ENTRYHI(i);
    406			buf->tlb_lo[0] = 0;
    407			buf->tlb_lo[1] = 0;
    408			buf->tlb_mask = 0;
    409		} else {
    410			/* Entry belongs to the right guest */
    411			buf->tlb_hi = read_gc0_entryhi();
    412			buf->tlb_lo[0] = read_gc0_entrylo0();
    413			buf->tlb_lo[1] = read_gc0_entrylo1();
    414			buf->tlb_mask = read_gc0_pagemask();
    415		}
    416	}
    417
    418	/* Clear root GuestID again */
    419	clear_root_gid();
    420	htw_start();
    421
    422	/* Restore clobbered registers */
    423	write_gc0_index(old_index);
    424	write_gc0_entryhi(old_entryhi);
    425	write_gc0_entrylo0(old_entrylo0);
    426	write_gc0_entrylo1(old_entrylo1);
    427	write_gc0_pagemask(old_pagemask);
    428
    429	tlbw_use_hazard();
    430}
    431EXPORT_SYMBOL_GPL(kvm_vz_save_guesttlb);
    432
    433/**
    434 * kvm_vz_load_guesttlb() - Save a range of guest TLB entries.
    435 * @buf:	Buffer to read TLB entries from.
    436 * @index:	Start index.
    437 * @count:	Number of entries to load.
    438 *
    439 * Load a range of guest TLB entries. The caller must ensure interrupts are
    440 * disabled.
    441 */
    442void kvm_vz_load_guesttlb(const struct kvm_mips_tlb *buf, unsigned int index,
    443			  unsigned int count)
    444{
    445	unsigned int end = index + count;
    446	unsigned long old_entryhi, old_entrylo0, old_entrylo1, old_pagemask;
    447	int old_index, i;
    448
    449	/* Save registers we're about to clobber */
    450	old_index = read_gc0_index();
    451	old_entryhi = read_gc0_entryhi();
    452	old_entrylo0 = read_gc0_entrylo0();
    453	old_entrylo1 = read_gc0_entrylo1();
    454	old_pagemask = read_gc0_pagemask();
    455
    456	/* Set root GuestID for root probe */
    457	htw_stop();
    458	set_root_gid_to_guest_gid();
    459
    460	/* Write each entry to guest TLB */
    461	for (i = index; i < end; ++i, ++buf) {
    462		write_gc0_index(i);
    463		write_gc0_entryhi(buf->tlb_hi);
    464		write_gc0_entrylo0(buf->tlb_lo[0]);
    465		write_gc0_entrylo1(buf->tlb_lo[1]);
    466		write_gc0_pagemask(buf->tlb_mask);
    467
    468		mtc0_tlbw_hazard();
    469		guest_tlb_write_indexed();
    470	}
    471
    472	/* Clear root GuestID again */
    473	clear_root_gid();
    474	htw_start();
    475
    476	/* Restore clobbered registers */
    477	write_gc0_index(old_index);
    478	write_gc0_entryhi(old_entryhi);
    479	write_gc0_entrylo0(old_entrylo0);
    480	write_gc0_entrylo1(old_entrylo1);
    481	write_gc0_pagemask(old_pagemask);
    482
    483	tlbw_use_hazard();
    484}
    485EXPORT_SYMBOL_GPL(kvm_vz_load_guesttlb);
    486
    487#ifdef CONFIG_CPU_LOONGSON64
    488void kvm_loongson_clear_guest_vtlb(void)
    489{
    490	int idx = read_gc0_index();
    491
    492	/* Set root GuestID for root probe and write of guest TLB entry */
    493	set_root_gid_to_guest_gid();
    494
    495	write_gc0_index(0);
    496	guest_tlbinvf();
    497	write_gc0_index(idx);
    498
    499	clear_root_gid();
    500	set_c0_diag(LOONGSON_DIAG_ITLB | LOONGSON_DIAG_DTLB);
    501}
    502EXPORT_SYMBOL_GPL(kvm_loongson_clear_guest_vtlb);
    503
    504void kvm_loongson_clear_guest_ftlb(void)
    505{
    506	int i;
    507	int idx = read_gc0_index();
    508
    509	/* Set root GuestID for root probe and write of guest TLB entry */
    510	set_root_gid_to_guest_gid();
    511
    512	for (i = current_cpu_data.tlbsizevtlb;
    513	     i < (current_cpu_data.tlbsizevtlb +
    514		     current_cpu_data.tlbsizeftlbsets);
    515	     i++) {
    516		write_gc0_index(i);
    517		guest_tlbinvf();
    518	}
    519	write_gc0_index(idx);
    520
    521	clear_root_gid();
    522	set_c0_diag(LOONGSON_DIAG_ITLB | LOONGSON_DIAG_DTLB);
    523}
    524EXPORT_SYMBOL_GPL(kvm_loongson_clear_guest_ftlb);
    525#endif