Hey Fuad,

On Tuesday 03 Aug 2021 at 07:31:03 (+0200), Fuad Tabba wrote:

Hi Quentin,

On Thu, Jul 29, 2021 at 3:29 PM Quentin Perret [off-list ref] wrote:

quoted

Refactor the hypervisor stage-1 locking in nVHE protected mode to expose
a new pkvm_create_mappings_locked() function. This will be used in later
patches to allow walking and changing the hypervisor stage-1 without
releasing the lock.

Signed-off-by: Quentin Perret <redacted>
---
 arch/arm64/kvm/hyp/include/nvhe/mm.h |  1 +
 arch/arm64/kvm/hyp/nvhe/mm.c         | 18 ++++++++++++++++--
 2 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/kvm/hyp/include/nvhe/mm.h b/arch/arm64/kvm/hyp/include/nvhe/mm.h
index 8ec3a5a7744b..c76d7136ed9b 100644
--- a/arch/arm64/kvm/hyp/include/nvhe/mm.h
+++ b/arch/arm64/kvm/hyp/include/nvhe/mm.h

@@ -23,6 +23,7 @@ int hyp_map_vectors(void);
 int hyp_back_vmemmap(phys_addr_t phys, unsigned long size, phys_addr_t back);
 int pkvm_cpu_set_vector(enum arm64_hyp_spectre_vector slot);
 int pkvm_create_mappings(void *from, void *to, enum kvm_pgtable_prot prot);
+int pkvm_create_mappings_locked(void *from, void *to, enum kvm_pgtable_prot prot);
 int __pkvm_create_mappings(unsigned long start, unsigned long size,
                           unsigned long phys, enum kvm_pgtable_prot prot);
 unsigned long __pkvm_create_private_mapping(phys_addr_t phys, size_t size,

diff --git a/arch/arm64/kvm/hyp/nvhe/mm.c b/arch/arm64/kvm/hyp/nvhe/mm.c
index a8efdf0f9003..6fbe8e8030f6 100644
--- a/arch/arm64/kvm/hyp/nvhe/mm.c
+++ b/arch/arm64/kvm/hyp/nvhe/mm.c

@@ -67,13 +67,15 @@ unsigned long __pkvm_create_private_mapping(phys_addr_t phys, size_t size,
        return addr;
 }

-int pkvm_create_mappings(void *from, void *to, enum kvm_pgtable_prot prot)
+int pkvm_create_mappings_locked(void *from, void *to, enum kvm_pgtable_prot prot)
 {
        unsigned long start = (unsigned long)from;
        unsigned long end = (unsigned long)to;
        unsigned long virt_addr;
        phys_addr_t phys;

+       hyp_assert_lock_held(&pkvm_pgd_lock);
+
        start = start & PAGE_MASK;
        end = PAGE_ALIGN(end);

@@ -81,7 +83,8 @@ int pkvm_create_mappings(void *from, void *to, enum kvm_pgtable_prot prot)
                int err;

                phys = hyp_virt_to_phys((void *)virt_addr);
-               err = __pkvm_create_mappings(virt_addr, PAGE_SIZE, phys, prot);
+               err = kvm_pgtable_hyp_map(&pkvm_pgtable, virt_addr, PAGE_SIZE,
+                                         phys, prot);
                if (err)
                        return err;
        }

@@ -89,6 +92,17 @@ int pkvm_create_mappings(void *from, void *to, enum kvm_pgtable_prot prot)
        return 0;
 }

+int pkvm_create_mappings(void *from, void *to, enum kvm_pgtable_prot prot)
+{
+       int ret;
+
+       hyp_spin_lock(&pkvm_pgd_lock);
+       ret = pkvm_create_mappings_locked(from, to, prot);
+       hyp_spin_unlock(&pkvm_pgd_lock);
+
+       return ret;
+}
+

I'm wondering whether this patch should also refactor
__pkvm_create_mappings. It doesn't quite do the exact same thing and
has different parameters.

Sorry, not sure I'm understanding your suggestion here. What do you
think should be done to __pkvm_create_mappings?

Cheers,
Quentin

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel