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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
This commit is contained in:
James Hogan 2017-03-14 10:15:27 +00:00
parent 1934a3ad09
commit 372582a6c6
3 changed files with 417 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
arch/mips/include/asm/cpu-info.h
View 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;
};

12
arch/mips/include/asm/kvm_host.h
View 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);

404
arch/mips/kvm/tlb.c
View File

@ -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.