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authorJames Hogan <james.hogan@imgtec.com>2017-03-14 11:15:27 +0100
committerJames Hogan <james.hogan@imgtec.com>2017-03-28 15:53:51 +0200
commit372582a6c6fcced38219d06545dd26ad7904bc6f (patch)
tree052d38b49752aae2caa78e050071b169f08c72f6 /arch/mips/kvm/tlb.c
parentKVM: MIPS/Entry: Update entry code to support VZ (diff)
downloadlinux-372582a6c6fcced38219d06545dd26ad7904bc6f.tar.xz
linux-372582a6c6fcced38219d06545dd26ad7904bc6f.zip
KVM: MIPS/TLB: Add VZ TLB management
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
Diffstat (limited to 'arch/mips/kvm/tlb.c')
-rw-r--r--arch/mips/kvm/tlb.c404
1 files changed, 404 insertions, 0 deletions
diff --git a/arch/mips/kvm/tlb.c b/arch/mips/kvm/tlb.c
index 2819eb793345..a28fcb1e5072 100644
--- a/arch/mips/kvm/tlb.c
+++ b/arch/mips/kvm/tlb.c
@@ -33,6 +33,18 @@
#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.