KVM: PPC: Book3s HV: Maintain separate guest and host views of R and C bits
This allows both the guest and the host to use the referenced (R) and
changed (C) bits in the guest hashed page table. The guest has a view
of R and C that is maintained in the guest_rpte field of the revmap
entry for the HPTE, and the host has a view that is maintained in the
rmap entry for the associated gfn.
Both view are updated from the guest HPT. If a bit (R or C) is zero
in either view, it will be initially set to zero in the HPTE (or HPTEs),
until set to 1 by hardware. When an HPTE is removed for any reason,
the R and C bits from the HPTE are ORed into both views. We have to
be careful to read the R and C bits from the HPTE after invalidating
it, but before unlocking it, in case of any late updates by the hardware.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
diff --git a/arch/powerpc/kvm/book3s_hv_rm_mmu.c b/arch/powerpc/kvm/book3s_hv_rm_mmu.c
index ba4a137..91b45a0 100644
--- a/arch/powerpc/kvm/book3s_hv_rm_mmu.c
+++ b/arch/powerpc/kvm/book3s_hv_rm_mmu.c
@@ -87,15 +87,17 @@
/* Remove this HPTE from the chain for a real page */
static void remove_revmap_chain(struct kvm *kvm, long pte_index,
- unsigned long hpte_v)
+ struct revmap_entry *rev,
+ unsigned long hpte_v, unsigned long hpte_r)
{
- struct revmap_entry *rev, *next, *prev;
+ struct revmap_entry *next, *prev;
unsigned long gfn, ptel, head;
struct kvm_memory_slot *memslot;
unsigned long *rmap;
+ unsigned long rcbits;
- rev = real_vmalloc_addr(&kvm->arch.revmap[pte_index]);
- ptel = rev->guest_rpte;
+ rcbits = hpte_r & (HPTE_R_R | HPTE_R_C);
+ ptel = rev->guest_rpte |= rcbits;
gfn = hpte_rpn(ptel, hpte_page_size(hpte_v, ptel));
memslot = builtin_gfn_to_memslot(kvm, gfn);
if (!memslot || (memslot->flags & KVM_MEMSLOT_INVALID))
@@ -116,6 +118,7 @@
else
*rmap = (*rmap & ~KVMPPC_RMAP_INDEX) | head;
}
+ *rmap |= rcbits << KVMPPC_RMAP_RC_SHIFT;
unlock_rmap(rmap);
}
@@ -162,6 +165,7 @@
pte_t pte;
unsigned int writing;
unsigned long mmu_seq;
+ unsigned long rcbits;
bool realmode = vcpu->arch.vcore->vcore_state == VCORE_RUNNING;
psize = hpte_page_size(pteh, ptel);
@@ -320,6 +324,9 @@
} else {
kvmppc_add_revmap_chain(kvm, rev, rmap, pte_index,
realmode);
+ /* Only set R/C in real HPTE if already set in *rmap */
+ rcbits = *rmap >> KVMPPC_RMAP_RC_SHIFT;
+ ptel &= rcbits | ~(HPTE_R_R | HPTE_R_C);
}
}
@@ -394,7 +401,8 @@
asm volatile("tlbiel %0" : : "r" (rb));
asm volatile("ptesync" : : : "memory");
}
- remove_revmap_chain(kvm, pte_index, v);
+ /* Read PTE low word after tlbie to get final R/C values */
+ remove_revmap_chain(kvm, pte_index, rev, v, hpte[1]);
}
r = rev->guest_rpte;
unlock_hpte(hpte, 0);
@@ -469,12 +477,13 @@
args[j] = ((0x80 | flags) << 56) + pte_index;
rev = real_vmalloc_addr(&kvm->arch.revmap[pte_index]);
- /* insert R and C bits from guest PTE */
- rcbits = rev->guest_rpte & (HPTE_R_R|HPTE_R_C);
- args[j] |= rcbits << (56 - 5);
- if (!(hp[0] & HPTE_V_VALID))
+ if (!(hp[0] & HPTE_V_VALID)) {
+ /* insert R and C bits from PTE */
+ rcbits = rev->guest_rpte & (HPTE_R_R|HPTE_R_C);
+ args[j] |= rcbits << (56 - 5);
continue;
+ }
hp[0] &= ~HPTE_V_VALID; /* leave it locked */
tlbrb[n] = compute_tlbie_rb(hp[0], hp[1], pte_index);
@@ -505,13 +514,16 @@
asm volatile("ptesync" : : : "memory");
}
+ /* Read PTE low words after tlbie to get final R/C values */
for (k = 0; k < n; ++k) {
j = indexes[k];
pte_index = args[j] & ((1ul << 56) - 1);
hp = hptes[k];
rev = revs[k];
- remove_revmap_chain(kvm, pte_index, hp[0]);
- unlock_hpte(hp, 0);
+ remove_revmap_chain(kvm, pte_index, rev, hp[0], hp[1]);
+ rcbits = rev->guest_rpte & (HPTE_R_R|HPTE_R_C);
+ args[j] |= rcbits << (56 - 5);
+ hp[0] = 0;
}
}
@@ -595,8 +607,7 @@
pte_index &= ~3;
n = 4;
}
- if (flags & H_R_XLATE)
- rev = real_vmalloc_addr(&kvm->arch.revmap[pte_index]);
+ rev = real_vmalloc_addr(&kvm->arch.revmap[pte_index]);
for (i = 0; i < n; ++i, ++pte_index) {
hpte = (unsigned long *)(kvm->arch.hpt_virt + (pte_index << 4));
v = hpte[0] & ~HPTE_V_HVLOCK;
@@ -605,12 +616,8 @@
v &= ~HPTE_V_ABSENT;
v |= HPTE_V_VALID;
}
- if (v & HPTE_V_VALID) {
- if (rev)
- r = rev[i].guest_rpte;
- else
- r = hpte[1] | HPTE_R_RPN;
- }
+ if (v & HPTE_V_VALID)
+ r = rev[i].guest_rpte | (r & (HPTE_R_R | HPTE_R_C));
vcpu->arch.gpr[4 + i * 2] = v;
vcpu->arch.gpr[5 + i * 2] = r;
}