Add a filtering hook that can get called on each level of the
walk, and providing access to the full state.
Crucially, this is called *before* the access is made, so that
it is possible to track down the level of a faulting access.
Signed-off-by: Marc Zyngier <maz@xxxxxxxxxx>
---
arch/arm64/include/asm/kvm_nested.h | 14 ++++++++++++++
arch/arm64/kvm/at.c | 11 +++++++++++
2 files changed, 25 insertions(+)
diff --git a/arch/arm64/include/asm/kvm_nested.h b/arch/arm64/include/asm/kvm_nested.h
index f3135ded47b7d..cce0e4cb54484 100644
--- a/arch/arm64/include/asm/kvm_nested.h
+++ b/arch/arm64/include/asm/kvm_nested.h
@@ -288,7 +288,21 @@ enum trans_regime {
TR_EL2,
};
+struct s1_walk_info;
+
+struct s1_walk_context {
+ struct s1_walk_info *wi;
+ u64 table_ipa;
+ int level;
+};
+
+struct s1_walk_filter {
+ int (*fn)(struct s1_walk_context *, void *);
+ void *priv;
+};
+
struct s1_walk_info {
+ struct s1_walk_filter *filter;
u64 baddr;
enum trans_regime regime;
unsigned int max_oa_bits;
diff --git a/arch/arm64/kvm/at.c b/arch/arm64/kvm/at.c
index 6e767ae3c495a..f77c16225557f 100644
--- a/arch/arm64/kvm/at.c
+++ b/arch/arm64/kvm/at.c
@@ -413,6 +413,17 @@ static int walk_s1(struct kvm_vcpu *vcpu, struct s1_walk_info *wi,
ipa = kvm_s2_trans_output(&s2_trans);
}
+ if (wi->filter) {
+ ret = wi->filter->fn(&(struct s1_walk_context)
+ {
+ .wi = wi,
+ .table_ipa = baddr,
+ .level = level,
+ }, wi->filter->priv);
+ if (ret)
+ return ret;
+ }
+
ret = kvm_read_guest(vcpu->kvm, ipa, &desc, sizeof(desc));
if (ret) {
fail_s1_walk(wr, ESR_ELx_FSC_SEA_TTW(level), false);
--
2.39.2
