KVM: MIPS/TLB: Add VZ TLB management
authorJames Hogan <james.hogan@imgtec.com>
Tue, 14 Mar 2017 10:15:27 +0000 (10:15 +0000)
committerJames Hogan <james.hogan@imgtec.com>
Tue, 28 Mar 2017 13:53:51 +0000 (14:53 +0100)
Add functions for MIPS VZ TLB management to tlb.c.

kvm_vz_host_tlb_inv() will be used for invalidating root TLB entries
after GPA page tables have been modified due to a KVM page fault. It
arranges for a root GPA mapping to be flushed from the TLB, using the
gpa_mm ASID or the current GuestID to do the probe.

kvm_vz_local_flush_roottlb_all_guests() and
kvm_vz_local_flush_guesttlb_all() flush all TLB entries in the
corresponding TLB for guest mappings (GPA->RPA for root TLB with
GuestID, and all entries for guest TLB). They will be used when starting
a new GuestID cycle, when VZ hardware is enabled/disabled, and also when
switching to a guest when the guest TLB contents may be stale or belong
to a different VM.

kvm_vz_guest_tlb_lookup() converts a guest virtual address to a guest
physical address using the guest TLB. This will be used to decode guest
virtual addresses which are sometimes provided by VZ hardware in
CP0_BadVAddr for certain exceptions when the guest physical address is
unavailable.

kvm_vz_save_guesttlb() and kvm_vz_load_guesttlb() will be used to
preserve wired guest VTLB entries while a guest isn't running.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Acked-by: Ralf Baechle <ralf@linux-mips.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
arch/mips/include/asm/cpu-info.h
arch/mips/include/asm/kvm_host.h
arch/mips/kvm/tlb.c

index edbe2734a1bf07ff6bef041881282d0ab968fb7c..4113796e0ef476679a3062afd7ff443213313110 100644 (file)
@@ -33,6 +33,7 @@ struct guest_info {
        unsigned long           ases_dyn;
        unsigned long long      options;
        unsigned long long      options_dyn;
+       int                     tlbsize;
        u8                      conf;
        u8                      kscratch_mask;
 };
index c52279d89ae47a60c902f85869a0ef969fb110a4..b47571850aacfb2105e3873a0e6e049661845720 100644 (file)
@@ -812,6 +812,18 @@ extern int kvm_mips_host_tlb_inv(struct kvm_vcpu *vcpu, unsigned long entryhi,
 extern int kvm_mips_guest_tlb_lookup(struct kvm_vcpu *vcpu,
                                     unsigned long entryhi);
 
+#ifdef CONFIG_KVM_MIPS_VZ
+int kvm_vz_host_tlb_inv(struct kvm_vcpu *vcpu, unsigned long entryhi);
+int kvm_vz_guest_tlb_lookup(struct kvm_vcpu *vcpu, unsigned long gva,
+                           unsigned long *gpa);
+void kvm_vz_local_flush_roottlb_all_guests(void);
+void kvm_vz_local_flush_guesttlb_all(void);
+void kvm_vz_save_guesttlb(struct kvm_mips_tlb *buf, unsigned int index,
+                         unsigned int count);
+void kvm_vz_load_guesttlb(const struct kvm_mips_tlb *buf, unsigned int index,
+                         unsigned int count);
+#endif
+
 void kvm_mips_suspend_mm(int cpu);
 void kvm_mips_resume_mm(int cpu);
 
index 2819eb793345abb41fd1a183edb67084f11acead..a28fcb1e50726139bccfdef5ec805e4ef77873bd 100644 (file)
 #define KVM_GUEST_PC_TLB    0
 #define KVM_GUEST_SP_TLB    1
 
+#ifdef CONFIG_KVM_MIPS_VZ
+static u32 kvm_mips_get_root_asid(struct kvm_vcpu *vcpu)
+{
+       struct mm_struct *gpa_mm = &vcpu->kvm->arch.gpa_mm;
+
+       if (cpu_has_guestid)
+               return 0;
+       else
+               return cpu_asid(smp_processor_id(), gpa_mm);
+}
+#endif
+
 static u32 kvm_mips_get_kernel_asid(struct kvm_vcpu *vcpu)
 {
        struct mm_struct *kern_mm = &vcpu->arch.guest_kernel_mm;
@@ -179,6 +191,398 @@ int kvm_mips_host_tlb_inv(struct kvm_vcpu *vcpu, unsigned long va,
 }
 EXPORT_SYMBOL_GPL(kvm_mips_host_tlb_inv);
 
+#ifdef CONFIG_KVM_MIPS_VZ
+
+/* GuestID management */
+
+/**
+ * clear_root_gid() - Set GuestCtl1.RID for normal root operation.
+ */
+static inline void clear_root_gid(void)
+{
+       if (cpu_has_guestid) {
+               clear_c0_guestctl1(MIPS_GCTL1_RID);
+               mtc0_tlbw_hazard();
+       }
+}
+
+/**
+ * set_root_gid_to_guest_gid() - Set GuestCtl1.RID to match GuestCtl1.ID.
+ *
+ * Sets the root GuestID to match the current guest GuestID, for TLB operation
+ * on the GPA->RPA mappings in the root TLB.
+ *
+ * The caller must be sure to disable HTW while the root GID is set, and
+ * possibly longer if TLB registers are modified.
+ */
+static inline void set_root_gid_to_guest_gid(void)
+{
+       unsigned int guestctl1;
+
+       if (cpu_has_guestid) {
+               back_to_back_c0_hazard();
+               guestctl1 = read_c0_guestctl1();
+               guestctl1 = (guestctl1 & ~MIPS_GCTL1_RID) |
+                       ((guestctl1 & MIPS_GCTL1_ID) >> MIPS_GCTL1_ID_SHIFT)
+                                                    << MIPS_GCTL1_RID_SHIFT;
+               write_c0_guestctl1(guestctl1);
+               mtc0_tlbw_hazard();
+       }
+}
+
+int kvm_vz_host_tlb_inv(struct kvm_vcpu *vcpu, unsigned long va)
+{
+       int idx;
+       unsigned long flags, old_entryhi;
+
+       local_irq_save(flags);
+       htw_stop();
+
+       /* Set root GuestID for root probe and write of guest TLB entry */
+       set_root_gid_to_guest_gid();
+
+       old_entryhi = read_c0_entryhi();
+
+       idx = _kvm_mips_host_tlb_inv((va & VPN2_MASK) |
+                                    kvm_mips_get_root_asid(vcpu));
+
+       write_c0_entryhi(old_entryhi);
+       clear_root_gid();
+       mtc0_tlbw_hazard();
+
+       htw_start();
+       local_irq_restore(flags);
+
+       if (idx > 0)
+               kvm_debug("%s: Invalidated root entryhi %#lx @ idx %d\n",
+                         __func__, (va & VPN2_MASK) |
+                                   kvm_mips_get_root_asid(vcpu), idx);
+
+       return 0;
+}
+EXPORT_SYMBOL_GPL(kvm_vz_host_tlb_inv);
+
+/**
+ * kvm_vz_guest_tlb_lookup() - Lookup a guest VZ TLB mapping.
+ * @vcpu:      KVM VCPU pointer.
+ * @gpa:       Guest virtual address in a TLB mapped guest segment.
+ * @gpa:       Ponter to output guest physical address it maps to.
+ *
+ * Converts a guest virtual address in a guest TLB mapped segment to a guest
+ * physical address, by probing the guest TLB.
+ *
+ * Returns:    0 if guest TLB mapping exists for @gva. *@gpa will have been
+ *             written.
+ *             -EFAULT if no guest TLB mapping exists for @gva. *@gpa may not
+ *             have been written.
+ */
+int kvm_vz_guest_tlb_lookup(struct kvm_vcpu *vcpu, unsigned long gva,
+                           unsigned long *gpa)
+{
+       unsigned long o_entryhi, o_entrylo[2], o_pagemask;
+       unsigned int o_index;
+       unsigned long entrylo[2], pagemask, pagemaskbit, pa;
+       unsigned long flags;
+       int index;
+
+       /* Probe the guest TLB for a mapping */
+       local_irq_save(flags);
+       /* Set root GuestID for root probe of guest TLB entry */
+       htw_stop();
+       set_root_gid_to_guest_gid();
+
+       o_entryhi = read_gc0_entryhi();
+       o_index = read_gc0_index();
+
+       write_gc0_entryhi((o_entryhi & 0x3ff) | (gva & ~0xfffl));
+       mtc0_tlbw_hazard();
+       guest_tlb_probe();
+       tlb_probe_hazard();
+
+       index = read_gc0_index();
+       if (index < 0) {
+               /* No match, fail */
+               write_gc0_entryhi(o_entryhi);
+               write_gc0_index(o_index);
+
+               clear_root_gid();
+               htw_start();
+               local_irq_restore(flags);
+               return -EFAULT;
+       }
+
+       /* Match! read the TLB entry */
+       o_entrylo[0] = read_gc0_entrylo0();
+       o_entrylo[1] = read_gc0_entrylo1();
+       o_pagemask = read_gc0_pagemask();
+
+       mtc0_tlbr_hazard();
+       guest_tlb_read();
+       tlb_read_hazard();
+
+       entrylo[0] = read_gc0_entrylo0();
+       entrylo[1] = read_gc0_entrylo1();
+       pagemask = ~read_gc0_pagemask() & ~0x1fffl;
+
+       write_gc0_entryhi(o_entryhi);
+       write_gc0_index(o_index);
+       write_gc0_entrylo0(o_entrylo[0]);
+       write_gc0_entrylo1(o_entrylo[1]);
+       write_gc0_pagemask(o_pagemask);
+
+       clear_root_gid();
+       htw_start();
+       local_irq_restore(flags);
+
+       /* Select one of the EntryLo values and interpret the GPA */
+       pagemaskbit = (pagemask ^ (pagemask & (pagemask - 1))) >> 1;
+       pa = entrylo[!!(gva & pagemaskbit)];
+
+       /*
+        * TLB entry may have become invalid since TLB probe if physical FTLB
+        * entries are shared between threads (e.g. I6400).
+        */
+       if (!(pa & ENTRYLO_V))
+               return -EFAULT;
+
+       /*
+        * Note, this doesn't take guest MIPS32 XPA into account, where PFN is
+        * split with XI/RI in the middle.
+        */
+       pa = (pa << 6) & ~0xfffl;
+       pa |= gva & ~(pagemask | pagemaskbit);
+
+       *gpa = pa;
+       return 0;
+}
+EXPORT_SYMBOL_GPL(kvm_vz_guest_tlb_lookup);
+
+/**
+ * kvm_vz_local_flush_roottlb_all_guests() - Flush all root TLB entries for
+ * guests.
+ *
+ * Invalidate all entries in root tlb which are GPA mappings.
+ */
+void kvm_vz_local_flush_roottlb_all_guests(void)
+{
+       unsigned long flags;
+       unsigned long old_entryhi, old_pagemask, old_guestctl1;
+       int entry;
+
+       if (WARN_ON(!cpu_has_guestid))
+               return;
+
+       local_irq_save(flags);
+       htw_stop();
+
+       /* TLBR may clobber EntryHi.ASID, PageMask, and GuestCtl1.RID */
+       old_entryhi = read_c0_entryhi();
+       old_pagemask = read_c0_pagemask();
+       old_guestctl1 = read_c0_guestctl1();
+
+       /*
+        * Invalidate guest entries in root TLB while leaving root entries
+        * intact when possible.
+        */
+       for (entry = 0; entry < current_cpu_data.tlbsize; entry++) {
+               write_c0_index(entry);
+               mtc0_tlbw_hazard();
+               tlb_read();
+               tlb_read_hazard();
+
+               /* Don't invalidate non-guest (RVA) mappings in the root TLB */
+               if (!(read_c0_guestctl1() & MIPS_GCTL1_RID))
+                       continue;
+
+               /* Make sure all entries differ. */
+               write_c0_entryhi(UNIQUE_ENTRYHI(entry));
+               write_c0_entrylo0(0);
+               write_c0_entrylo1(0);
+               write_c0_guestctl1(0);
+               mtc0_tlbw_hazard();
+               tlb_write_indexed();
+       }
+
+       write_c0_entryhi(old_entryhi);
+       write_c0_pagemask(old_pagemask);
+       write_c0_guestctl1(old_guestctl1);
+       tlbw_use_hazard();
+
+       htw_start();
+       local_irq_restore(flags);
+}
+EXPORT_SYMBOL_GPL(kvm_vz_local_flush_roottlb_all_guests);
+
+/**
+ * kvm_vz_local_flush_guesttlb_all() - Flush all guest TLB entries.
+ *
+ * Invalidate all entries in guest tlb irrespective of guestid.
+ */
+void kvm_vz_local_flush_guesttlb_all(void)
+{
+       unsigned long flags;
+       unsigned long old_index;
+       unsigned long old_entryhi;
+       unsigned long old_entrylo[2];
+       unsigned long old_pagemask;
+       int entry;
+
+       local_irq_save(flags);
+
+       /* Preserve all clobbered guest registers */
+       old_index = read_gc0_index();
+       old_entryhi = read_gc0_entryhi();
+       old_entrylo[0] = read_gc0_entrylo0();
+       old_entrylo[1] = read_gc0_entrylo1();
+       old_pagemask = read_gc0_pagemask();
+
+       /* Invalidate guest entries in guest TLB */
+       write_gc0_entrylo0(0);
+       write_gc0_entrylo1(0);
+       write_gc0_pagemask(0);
+       for (entry = 0; entry < current_cpu_data.guest.tlbsize; entry++) {
+               /* Make sure all entries differ. */
+               write_gc0_index(entry);
+               write_gc0_entryhi(UNIQUE_GUEST_ENTRYHI(entry));
+               mtc0_tlbw_hazard();
+               guest_tlb_write_indexed();
+       }
+       write_gc0_index(old_index);
+       write_gc0_entryhi(old_entryhi);
+       write_gc0_entrylo0(old_entrylo[0]);
+       write_gc0_entrylo1(old_entrylo[1]);
+       write_gc0_pagemask(old_pagemask);
+       tlbw_use_hazard();
+
+       local_irq_restore(flags);
+}
+EXPORT_SYMBOL_GPL(kvm_vz_local_flush_guesttlb_all);
+
+/**
+ * kvm_vz_save_guesttlb() - Save a range of guest TLB entries.
+ * @buf:       Buffer to write TLB entries into.
+ * @index:     Start index.
+ * @count:     Number of entries to save.
+ *
+ * Save a range of guest TLB entries. The caller must ensure interrupts are
+ * disabled.
+ */
+void kvm_vz_save_guesttlb(struct kvm_mips_tlb *buf, unsigned int index,
+                         unsigned int count)
+{
+       unsigned int end = index + count;
+       unsigned long old_entryhi, old_entrylo0, old_entrylo1, old_pagemask;
+       unsigned int guestctl1 = 0;
+       int old_index, i;
+
+       /* Save registers we're about to clobber */
+       old_index = read_gc0_index();
+       old_entryhi = read_gc0_entryhi();
+       old_entrylo0 = read_gc0_entrylo0();
+       old_entrylo1 = read_gc0_entrylo1();
+       old_pagemask = read_gc0_pagemask();
+
+       /* Set root GuestID for root probe */
+       htw_stop();
+       set_root_gid_to_guest_gid();
+       if (cpu_has_guestid)
+               guestctl1 = read_c0_guestctl1();
+
+       /* Read each entry from guest TLB */
+       for (i = index; i < end; ++i, ++buf) {
+               write_gc0_index(i);
+
+               mtc0_tlbr_hazard();
+               guest_tlb_read();
+               tlb_read_hazard();
+
+               if (cpu_has_guestid &&
+                   (read_c0_guestctl1() ^ guestctl1) & MIPS_GCTL1_RID) {
+                       /* Entry invalid or belongs to another guest */
+                       buf->tlb_hi = UNIQUE_GUEST_ENTRYHI(i);
+                       buf->tlb_lo[0] = 0;
+                       buf->tlb_lo[1] = 0;
+                       buf->tlb_mask = 0;
+               } else {
+                       /* Entry belongs to the right guest */
+                       buf->tlb_hi = read_gc0_entryhi();
+                       buf->tlb_lo[0] = read_gc0_entrylo0();
+                       buf->tlb_lo[1] = read_gc0_entrylo1();
+                       buf->tlb_mask = read_gc0_pagemask();
+               }
+       }
+
+       /* Clear root GuestID again */
+       clear_root_gid();
+       htw_start();
+
+       /* Restore clobbered registers */
+       write_gc0_index(old_index);
+       write_gc0_entryhi(old_entryhi);
+       write_gc0_entrylo0(old_entrylo0);
+       write_gc0_entrylo1(old_entrylo1);
+       write_gc0_pagemask(old_pagemask);
+
+       tlbw_use_hazard();
+}
+EXPORT_SYMBOL_GPL(kvm_vz_save_guesttlb);
+
+/**
+ * kvm_vz_load_guesttlb() - Save a range of guest TLB entries.
+ * @buf:       Buffer to read TLB entries from.
+ * @index:     Start index.
+ * @count:     Number of entries to load.
+ *
+ * Load a range of guest TLB entries. The caller must ensure interrupts are
+ * disabled.
+ */
+void kvm_vz_load_guesttlb(const struct kvm_mips_tlb *buf, unsigned int index,
+                         unsigned int count)
+{
+       unsigned int end = index + count;
+       unsigned long old_entryhi, old_entrylo0, old_entrylo1, old_pagemask;
+       int old_index, i;
+
+       /* Save registers we're about to clobber */
+       old_index = read_gc0_index();
+       old_entryhi = read_gc0_entryhi();
+       old_entrylo0 = read_gc0_entrylo0();
+       old_entrylo1 = read_gc0_entrylo1();
+       old_pagemask = read_gc0_pagemask();
+
+       /* Set root GuestID for root probe */
+       htw_stop();
+       set_root_gid_to_guest_gid();
+
+       /* Write each entry to guest TLB */
+       for (i = index; i < end; ++i, ++buf) {
+               write_gc0_index(i);
+               write_gc0_entryhi(buf->tlb_hi);
+               write_gc0_entrylo0(buf->tlb_lo[0]);
+               write_gc0_entrylo1(buf->tlb_lo[1]);
+               write_gc0_pagemask(buf->tlb_mask);
+
+               mtc0_tlbw_hazard();
+               guest_tlb_write_indexed();
+       }
+
+       /* Clear root GuestID again */
+       clear_root_gid();
+       htw_start();
+
+       /* Restore clobbered registers */
+       write_gc0_index(old_index);
+       write_gc0_entryhi(old_entryhi);
+       write_gc0_entrylo0(old_entrylo0);
+       write_gc0_entrylo1(old_entrylo1);
+       write_gc0_pagemask(old_pagemask);
+
+       tlbw_use_hazard();
+}
+EXPORT_SYMBOL_GPL(kvm_vz_load_guesttlb);
+
+#endif
+
 /**
  * kvm_mips_suspend_mm() - Suspend the active mm.
  * @cpu                The CPU we're running on.