[PATCH 03/12] KVM: PPC: E500: Propagate errors when shadow mapping

Alexander Graf
2013-02-15T00:16:19Z

When shadow mapping a page, mapping this page can fail. In that case we
don't have a shadow map.

Take this case into account, otherwise we might end up writing bogus TLB
entries into the host TLB.

While at it, also move the write_stlbe() calls into the respective TLBn
handlers.

Signed-off-by: Alexander Graf <agraf@suse.de>
---
arch/powerpc/kvm/e500_tlb.c | 69 +++++++++++++++++++++++++-----------------
1 files changed, 41 insertions(+), 28 deletions(-)

diff --git a/arch/powerpc/kvm/e500_tlb.c b/arch/powerpc/kvm/e500_tlb.c
index 8efb2ac..3777167 100644
--- a/arch/powerpc/kvm/e500_tlb.c
+++ b/arch/powerpc/kvm/e500_tlb.c
@@ -432,7 +432,7 @@ static inline void kvmppc_e500_setup_stlbe(
#endif
}

-static inline void kvmppc_e500_shadow_map(struct kvmppc_vcpu_e500 *vcpu_e500,
+static inline int kvmppc_e500_shadow_map(struct kvmppc_vcpu_e500 *vcpu_e500,
u64 gvaddr, gfn_t gfn, struct kvm_book3e_206_tlb_entry *gtlbe,
int tlbsel, struct kvm_book3e_206_tlb_entry *stlbe,
struct tlbe_ref *ref)
@@ -551,7 +551,7 @@ static inline void kvmppc_e500_shadow_map(struct kvmppc_vcpu_e500 *vcpu_e500,
if (is_error_noslot_pfn(pfn)) {
printk(KERN_ERR "Couldn't get real page for gfn %lx!\n",
(long)gfn);
- return;
+ return -EINVAL;
}

/* Align guest and physical address to page map boundaries */
@@ -571,22 +571,33 @@ static inline void kvmppc_e500_shadow_map(struct kvmppc_vcpu_e500 *vcpu_e500,

/* Drop refcount on page, so that mmu notifiers can clear it */
kvm_release_pfn_clean(pfn);
+
+ return 0;
}

/* XXX only map the one-one case, for now use TLB0 */
-static void kvmppc_e500_tlb0_map(struct kvmppc_vcpu_e500 *vcpu_e500,
- int esel,
- struct kvm_book3e_206_tlb_entry *stlbe)
+static int kvmppc_e500_tlb0_map(struct kvmppc_vcpu_e500 *vcpu_e500,
+ int esel,
+ struct kvm_book3e_206_tlb_entry *stlbe)
{
struct kvm_book3e_206_tlb_entry *gtlbe;
struct tlbe_ref *ref;
+ int stlbsel = 0;
+ int sesel = 0;
+ int r;

gtlbe = get_entry(vcpu_e500, 0, esel);
ref = &vcpu_e500->gtlb_priv[0][esel].ref;

- kvmppc_e500_shadow_map(vcpu_e500, get_tlb_eaddr(gtlbe),
+ r = kvmppc_e500_shadow_map(vcpu_e500, get_tlb_eaddr(gtlbe),
get_tlb_raddr(gtlbe) >> PAGE_SHIFT,
gtlbe, 0, stlbe, ref);
+ if (r)
+ return r;
+
+ write_stlbe(vcpu_e500, gtlbe, stlbe, stlbsel, sesel);
+
+ return 0;
}

/* Caller must ensure that the specified guest TLB entry is safe to insert into
@@ -597,25 +608,32 @@ static int kvmppc_e500_tlb1_map(struct kvmppc_vcpu_e500 *vcpu_e500,
struct kvm_book3e_206_tlb_entry *stlbe, int esel)
{
struct tlbe_ref *ref;
- unsigned int victim;
+ unsigned int sesel;
+ int r;
+ int stlbsel = 1;

- victim = vcpu_e500->host_tlb1_nv++;
+ sesel = vcpu_e500->host_tlb1_nv++;

if (unlikely(vcpu_e500->host_tlb1_nv >= tlb1_max_shadow_size()))
vcpu_e500->host_tlb1_nv = 0;

- ref = &vcpu_e500->tlb_refs[1][victim];
- kvmppc_e500_shadow_map(vcpu_e500, gvaddr, gfn, gtlbe, 1, stlbe, ref);
+ ref = &vcpu_e500->tlb_refs[1][sesel];
+ r = kvmppc_e500_shadow_map(vcpu_e500, gvaddr, gfn, gtlbe, 1, stlbe,
+ ref);
+ if (r)
+ return r;

- vcpu_e500->g2h_tlb1_map[esel] |= (u64)1 << victim;
+ vcpu_e500->g2h_tlb1_map[esel] |= (u64)1 << sesel;
vcpu_e500->gtlb_priv[1][esel].ref.flags |= E500_TLB_BITMAP;
- if (vcpu_e500->h2g_tlb1_rmap[victim]) {
- unsigned int idx = vcpu_e500->h2g_tlb1_rmap[victim];
- vcpu_e500->g2h_tlb1_map[idx] &= ~(1ULL << victim);
+ if (vcpu_e500->h2g_tlb1_rmap[sesel]) {
+ unsigned int idx = vcpu_e500->h2g_tlb1_rmap[sesel];
+ vcpu_e500->g2h_tlb1_map[idx] &= ~(1ULL << sesel);
}
- vcpu_e500->h2g_tlb1_rmap[victim] = esel;
+ vcpu_e500->h2g_tlb1_rmap[sesel] = esel;

- return victim;
+ write_stlbe(vcpu_e500, gtlbe, stlbe, stlbsel, sesel);
+
+ return 0;
}

static void kvmppc_recalc_tlb1map_range(struct kvmppc_vcpu_e500 *vcpu_e500)
@@ -1034,30 +1052,27 @@ void kvmppc_mmu_map(struct kvm_vcpu *vcpu, u64 eaddr, gpa_t gpaddr,
struct kvm_book3e_206_tlb_entry *gtlbe, stlbe;
int tlbsel = tlbsel_of(index);
int esel = esel_of(index);
- int stlbsel, sesel;

gtlbe = get_entry(vcpu_e500, tlbsel, esel);

switch (tlbsel) {
case 0:
- stlbsel = 0;
- sesel = 0; /* unused */
priv = &vcpu_e500->gtlb_priv[tlbsel][esel];

- /* Only triggers after clear_tlb_refs */
- if (unlikely(!(priv->ref.flags & E500_TLB_VALID)))
+ /* Triggers after clear_tlb_refs or on initial mapping */
+ if (!(priv->ref.flags & E500_TLB_VALID)) {
kvmppc_e500_tlb0_map(vcpu_e500, esel, &stlbe);
- else
+ } else {
kvmppc_e500_setup_stlbe(vcpu, gtlbe, BOOK3E_PAGESZ_4K,
&priv->ref, eaddr, &stlbe);
+ write_stlbe(vcpu_e500, gtlbe, &stlbe, 0, 0);
+ }
break;

case 1: {
gfn_t gfn = gpaddr >> PAGE_SHIFT;
-
- stlbsel = 1;
- sesel = kvmppc_e500_tlb1_map(vcpu_e500, eaddr, gfn,
- gtlbe, &stlbe, esel);
+ kvmppc_e500_tlb1_map(vcpu_e500, eaddr, gfn, gtlbe, &stlbe,
+ esel);
break;
}

@@ -1065,8 +1080,6 @@ void kvmppc_mmu_map(struct kvm_vcpu *vcpu, u64 eaddr, gpa_t gpaddr,
BUG();
break;
}
-
- write_stlbe(vcpu_e500, gtlbe, &stlbe, stlbsel, sesel);
}

/************* MMU Notifiers *************/
--
1.6.0.2