Thread (45 messages) 45 messages, 2 authors, 2021-08-03

Re: [PATCH v3 13/21] KVM: arm64: Expose host stage-2 manipulation helpers

From: Fuad Tabba <hidden>
Date: 2021-08-02 11:14:09
Also in: kvmarm, lkml

Hi Quentin,

On Thu, Jul 29, 2021 at 3:28 PM Quentin Perret [off-list ref] wrote:
quoted hunk ↗ jump to hunk
We will need to manipulate the host stage-2 page-table from outside
mem_protect.c soon. Introduce two functions allowing this, and make
them usable to users of mem_protect.h.

Signed-off-by: Quentin Perret <redacted>
---
 arch/arm64/kvm/hyp/include/nvhe/mem_protect.h |  2 ++
 arch/arm64/kvm/hyp/nvhe/mem_protect.c         | 17 ++++++++++++++++-
 2 files changed, 18 insertions(+), 1 deletion(-)
diff --git a/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h b/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h
index ae355bfd8c01..47c2a0c51612 100644
--- a/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h
+++ b/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h
@@ -49,6 +49,8 @@ extern struct host_kvm host_kvm;
 int __pkvm_prot_finalize(void);
 int __pkvm_mark_hyp(phys_addr_t start, phys_addr_t end);

+int host_stage2_idmap_locked(u64 start, u64 end, enum kvm_pgtable_prot prot);
+int host_stage2_set_owner_locked(u64 start, u64 end, u8 owner_id);
 int kvm_host_prepare_stage2(void *pgt_pool_base);
 void handle_host_mem_abort(struct kvm_cpu_context *host_ctxt);
diff --git a/arch/arm64/kvm/hyp/nvhe/mem_protect.c b/arch/arm64/kvm/hyp/nvhe/mem_protect.c
index 70c57d2c3024..a7f6134789e0 100644
--- a/arch/arm64/kvm/hyp/nvhe/mem_protect.c
+++ b/arch/arm64/kvm/hyp/nvhe/mem_protect.c
@@ -272,6 +272,21 @@ static int host_stage2_adjust_range(u64 addr, struct kvm_mem_range *range)
        return 0;
 }

+int host_stage2_idmap_locked(u64 start, u64 end, enum kvm_pgtable_prot prot)
+{
+       hyp_assert_lock_held(&host_kvm.lock);
+
+       return host_stage2_try(__host_stage2_idmap, start, end, prot);
+}
+
+int host_stage2_set_owner_locked(u64 start, u64 end, u8 owner_id)
+{
+       hyp_assert_lock_held(&host_kvm.lock);
+
+       return host_stage2_try(kvm_pgtable_stage2_set_owner, &host_kvm.pgt,
+                              start, end - start, &host_s2_pool, owner_id);
+}
This is a potential issue elsewhere as well, but all functions in
kvm_pgtable.h, including kvm_pgtable_stage2_set_owner, specify an
address range via address and size. The two you have introduced here
take a start and an end. I'm not sure if making these two consistent
with the ones in kvm_pgtable.h would be good, or would just complicate
things in other places.

Thanks,
/fuad
quoted hunk ↗ jump to hunk
 static bool host_stage2_force_pte_cb(u64 addr, u64 end, enum kvm_pgtable_prot prot)
 {
        /*
@@ -309,7 +324,7 @@ static int host_stage2_idmap(u64 addr)
        if (ret)
                goto unlock;

-       ret = host_stage2_try(__host_stage2_idmap, range.start, range.end, prot);
+       ret = host_stage2_idmap_locked(range.start, range.end, prot);
 unlock:
        hyp_spin_unlock(&host_kvm.lock);

--
2.32.0.432.gabb21c7263-goog
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