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Commit 372582a6 authored by James Hogan's avatar James Hogan
Browse files

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: default avatarJames Hogan <james.hogan@imgtec.com>
Acked-by: default avatarRalf 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
parent 1934a3ad

arch/mips/include/asm/cpu-info.h

+1 −0
Original line number Diff line number Diff line
@@ -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;

};

arch/mips/include/asm/kvm_host.h

+12 −0
Original line number Diff line number Diff line
@@ -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);

arch/mips/kvm/tlb.c

+404 −0
Original line number Diff line number Diff line
@@ -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.