KVM: arm64: Don't unnecessarily map host kernel sections at EL2

We no longer need to map the host's '.rodata' and '.bss' sections in the
stage-1 page-table of the pKVM hypervisor at EL2, so remove those
mappings and avoid creating any future dependencies at EL2 on
host-controlled data structures.

Tested-by: Vincent Donnefort <vdonnefort@google.com>
Signed-off-by: Quentin Perret <qperret@google.com>
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20221110190259.26861-25-will@kernel.org

diff --git a/arch/arm64/kernel/image-vars.h b/arch/arm64/kernel/image-vars.h
index 31ad75d..e3f88b5 100644 (file)
--- a/arch/arm64/kernel/image-vars.h
+++ b/arch/arm64/kernel/image-vars.h
@@ -102,12 +102,6 @@ KVM_NVHE_ALIAS_HYP(__memcpy, __pi_memcpy);
 KVM_NVHE_ALIAS_HYP(__memset, __pi_memset);
 #endif
 
-/* Kernel memory sections */
-KVM_NVHE_ALIAS(__start_rodata);
-KVM_NVHE_ALIAS(__end_rodata);
-KVM_NVHE_ALIAS(__bss_start);
-KVM_NVHE_ALIAS(__bss_stop);
-
 /* Hyp memory sections */
 KVM_NVHE_ALIAS(__hyp_idmap_text_start);
 KVM_NVHE_ALIAS(__hyp_idmap_text_end);

diff --git a/arch/arm64/kvm/hyp/nvhe/setup.c b/arch/arm64/kvm/hyp/nvhe/setup.c
index 5a371ab..5cdf3fb 100644 (file)
--- a/arch/arm64/kvm/hyp/nvhe/setup.c
+++ b/arch/arm64/kvm/hyp/nvhe/setup.c
@@ -144,23 +144,15 @@ static int recreate_hyp_mappings(phys_addr_t phys, unsigned long size,
        }
 
        /*
-        * Map the host's .bss and .rodata sections RO in the hypervisor, but
-        * transfer the ownership from the host to the hypervisor itself to
-        * make sure it can't be donated or shared with another entity.
+        * Map the host sections RO in the hypervisor, but transfer the
+        * ownership from the host to the hypervisor itself to make sure they
+        * can't be donated or shared with another entity.
         *
         * The ownership transition requires matching changes in the host
         * stage-2. This will be done later (see finalize_host_mappings()) once
         * the hyp_vmemmap is addressable.
         */
        prot = pkvm_mkstate(PAGE_HYP_RO, PKVM_PAGE_SHARED_OWNED);
-       ret = pkvm_create_mappings(__start_rodata, __end_rodata, prot);
-       if (ret)
-               return ret;
-
-       ret = pkvm_create_mappings(__hyp_bss_end, __bss_stop, prot);
-       if (ret)
-               return ret;
-
        ret = pkvm_create_mappings(&kvm_vgic_global_state,
                                   &kvm_vgic_global_state + 1, prot);
        if (ret)