arm64: KVM: force cache clean on page fault when caches are off

In order for the guest with caches off to observe data written
contained in a given page, we need to make sure that page is
committed to memory, and not just hanging in the cache (as
guest accesses are completely bypassing the cache until it
decides to enable it).

For this purpose, hook into the coherent_icache_guest_page
function and flush the region if the guest SCTLR_EL1
register doesn't show the MMU  and caches as being enabled.
The function also get renamed to coherent_cache_guest_page.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>

1 files changed, 2 insertions, 2 deletions

diff --git a/arch/arm/kvm/mmu.c b/arch/arm/kvm/mmu.c
index 7789857d1470..fc71a8df0e13 100644
--- a/arch/arm/kvm/mmu.c
+++ b/arch/arm/kvm/mmu.c
@@ -715,7 +715,7 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
                         kvm_set_s2pmd_writable(&new_pmd);
                         kvm_set_pfn_dirty(pfn);
                 }
-                coherent_icache_guest_page(kvm, hva & PMD_MASK, PMD_SIZE);
+                coherent_cache_guest_page(vcpu, hva & PMD_MASK, PMD_SIZE);
                 ret = stage2_set_pmd_huge(kvm, memcache, fault_ipa, &new_pmd);
         } else {
                 pte_t new_pte = pfn_pte(pfn, PAGE_S2);
@@ -723,7 +723,7 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
                         kvm_set_s2pte_writable(&new_pte);
                         kvm_set_pfn_dirty(pfn);
                 }
-                coherent_icache_guest_page(kvm, hva, PAGE_SIZE);
+                coherent_cache_guest_page(vcpu, hva, PAGE_SIZE);
                 ret = stage2_set_pte(kvm, memcache, fault_ipa, &new_pte, false);
         }