Hi Ard,
On 2014-09-13 11:17, Ard Biesheuvel wrote:
Now that we support read-only memslots, we need to make sure that
pass-through device mappings are not mapped writable if the guest
has requested them to be read-only. The existing implementation
already honours this by calling kvm_set_s2pte_writable() on the new
pte in case of writable mappings, so all we need to do is define
the default pgprot_t value used for devices to be PTE_S2_RDONLY.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
I feel very uncomfortable with this change. Why would we map a device
RO? Is that only for completeness sake?
Note that we also use PAGE_S2_DEVICE for things that are not mapped
through a memslot, such as the GIC.
Thanks,
M.
---
arch/arm/include/asm/pgtable.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/arm/include/asm/pgtable.h
b/arch/arm/include/asm/pgtable.h
index 01baef07cd0c..92b2fbe18868 100644
--- a/arch/arm/include/asm/pgtable.h
+++ b/arch/arm/include/asm/pgtable.h
@@ -100,7 +100,7 @@ extern pgprot_t pgprot_s2_device;
#define PAGE_HYP _MOD_PROT(pgprot_kernel, L_PTE_HYP)
#define PAGE_HYP_DEVICE _MOD_PROT(pgprot_hyp_device, L_PTE_HYP)
#define PAGE_S2 _MOD_PROT(pgprot_s2, L_PTE_S2_RDONLY)
-#define PAGE_S2_DEVICE _MOD_PROT(pgprot_s2_device, L_PTE_S2_RDWR)
+#define PAGE_S2_DEVICE _MOD_PROT(pgprot_s2_device, L_PTE_S2_RDONLY)
#define __PAGE_NONE __pgprot(_L_PTE_DEFAULT | L_PTE_RDONLY |
L_PTE_XN | L_PTE_NONE)
#define __PAGE_SHARED __pgprot(_L_PTE_DEFAULT | L_PTE_USER |
L_PTE_XN)
--
Fast, cheap, reliable. Pick two.
_______________________________________________
kvmarm mailing list
kvmarm@xxxxxxxxxxxxxxxxxxxxx
https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
