The kvm_unmap_rmapp() function, called from certain MMU notifiers, is used
to force all guest mappings of a particular host page to be set ABSENT, and
removed from the reverse mappings.
For HPT resizing, we will have some cases where we want to set just a
single guest HPTE ABSENT and remove its reverse mappings. To prepare with
this, we split out the logic from kvm_unmap_rmapp() to evict a single HPTE,
moving it to a new helper function.
Signed-off-by: David Gibson <da...@gibson.dropbear.id.au>
---
arch/powerpc/kvm/book3s_64_mmu_hv.c | 77 +++++++++++++++++++++----------------
1 file changed, 44 insertions(+), 33 deletions(-)
diff --git a/arch/powerpc/kvm/book3s_64_mmu_hv.c
b/arch/powerpc/kvm/book3s_64_mmu_hv.c
index 8e5ac2f..cd145eb 100644
--- a/arch/powerpc/kvm/book3s_64_mmu_hv.c
+++ b/arch/powerpc/kvm/book3s_64_mmu_hv.c
@@ -740,13 +740,53 @@ static int kvm_handle_hva(struct kvm *kvm, unsigned long
hva,
return kvm_handle_hva_range(kvm, hva, hva + 1, handler);
}
+/* Must be called with both HPTE and rmap locked */
+static void kvmppc_unmap_hpte(struct kvm *kvm, unsigned long i,
+ unsigned long *rmapp, unsigned long gfn)
+{
+ __be64 *hptep = (__be64 *) (kvm->arch.hpt.virt + (i << 4));
+ struct revmap_entry *rev = kvm->arch.hpt.rev;
+ unsigned long j, h;
+ unsigned long ptel, psize, rcbits;
+
+ j = rev[i].forw;
+ if (j == i) {
+ /* chain is now empty */
+ *rmapp &= ~(KVMPPC_RMAP_PRESENT | KVMPPC_RMAP_INDEX);
+ } else {
+ /* remove i from chain */
+ h = rev[i].back;
+ rev[h].forw = j;
+ rev[j].back = h;
+ rev[i].forw = rev[i].back = i;
+ *rmapp = (*rmapp & ~KVMPPC_RMAP_INDEX) | j;
+ }
+
+ /* Now check and modify the HPTE */
+ ptel = rev[i].guest_rpte;
+ psize = hpte_page_size(be64_to_cpu(hptep[0]), ptel);
+ if ((be64_to_cpu(hptep[0]) & HPTE_V_VALID) &&
+ hpte_rpn(ptel, psize) == gfn) {
+ hptep[0] |= cpu_to_be64(HPTE_V_ABSENT);
+ kvmppc_invalidate_hpte(kvm, hptep, i);
+ hptep[1] &= ~cpu_to_be64(HPTE_R_KEY_HI | HPTE_R_KEY_LO);
+ /* Harvest R and C */
+ rcbits = be64_to_cpu(hptep[1]) & (HPTE_R_R | HPTE_R_C);
+ *rmapp |= rcbits << KVMPPC_RMAP_RC_SHIFT;
+ if (rcbits & HPTE_R_C)
+ kvmppc_update_rmap_change(rmapp, psize);
+ if (rcbits & ~rev[i].guest_rpte) {
+ rev[i].guest_rpte = ptel | rcbits;
+ note_hpte_modification(kvm, &rev[i]);
+ }
+ }
+}
+
static int kvm_unmap_rmapp(struct kvm *kvm, unsigned long *rmapp,
unsigned long gfn)
{
- struct revmap_entry *rev = kvm->arch.hpt.rev;
- unsigned long h, i, j;
+ unsigned long i;
__be64 *hptep;
- unsigned long ptel, psize, rcbits;
for (;;) {
lock_rmap(rmapp);
@@ -769,37 +809,8 @@ static int kvm_unmap_rmapp(struct kvm *kvm, unsigned long
*rmapp,
cpu_relax();
continue;
}
- j = rev[i].forw;
- if (j == i) {
- /* chain is now empty */
- *rmapp &= ~(KVMPPC_RMAP_PRESENT | KVMPPC_RMAP_INDEX);
- } else {
- /* remove i from chain */
- h = rev[i].back;
- rev[h].forw = j;
- rev[j].back = h;
- rev[i].forw = rev[i].back = i;
- *rmapp = (*rmapp & ~KVMPPC_RMAP_INDEX) | j;
- }
- /* Now check and modify the HPTE */
- ptel = rev[i].guest_rpte;
- psize = hpte_page_size(be64_to_cpu(hptep[0]), ptel);
- if ((be64_to_cpu(hptep[0]) & HPTE_V_VALID) &&
- hpte_rpn(ptel, psize) == gfn) {
- hptep[0] |= cpu_to_be64(HPTE_V_ABSENT);
- kvmppc_invalidate_hpte(kvm, hptep, i);
- hptep[1] &= ~cpu_to_be64(HPTE_R_KEY_HI | HPTE_R_KEY_LO);
- /* Harvest R and C */
- rcbits = be64_to_cpu(hptep[1]) & (HPTE_R_R | HPTE_R_C);
- *rmapp |= rcbits << KVMPPC_RMAP_RC_SHIFT;
- if (rcbits & HPTE_R_C)
- kvmppc_update_rmap_change(rmapp, psize);
- if (rcbits & ~rev[i].guest_rpte) {
- rev[i].guest_rpte = ptel | rcbits;
- note_hpte_modification(kvm, &rev[i]);
- }
- }
+ kvmppc_unmap_hpte(kvm, i, rmapp, gfn);
unlock_rmap(rmapp);
__unlock_hpte(hptep, be64_to_cpu(hptep[0]));
}
--
2.9.3
