When the guest runs with caches disabled (like in an early boot
sequence, for example), all the writes are diectly going to RAM,
bypassing the caches altogether.
Once the MMU and caches are enabled, whatever sits in the cache
becomes suddenly visible, which isn't what the guest expects.
A way to avoid this potential disaster is to invalidate the cache
when the MMU is being turned on. For this, we hook into the SCTLR_EL1
trapping code, and scan the stage-2 page tables, invalidating the
pages/sections that have already been mapped in.
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>
The use of p*d_addr_end with stage-2 translation is slightly dodgy,
as the IPA is 40bits, while all the p*d_addr_end helpers are
taking an unsigned long (arm64 is fine with that as unligned long
is 64bit).
The fix is to introduce 64bit clean versions of the same helpers,
and use them in the stage-2 page table code.
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
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>
KVM initialisation fails on architectures implementing virt_to_idmap()
because virt_to_phys() on such architectures won't fetch you the correct
idmap page.
So update the KVM ARM code to use the virt_to_idmap() to fix the issue.
Since the KVM code is shared between arm and arm64, we create
kvm_virt_to_phys() and handle the redirection in respective headers.
Cc: Christoffer Dall <christoffer.dall@linaro.org>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
Support huge pages in KVM/ARM and KVM/ARM64. The pud_huge checking on
the unmap path may feel a bit silly as the pud_huge check is always
defined to false, but the compiler should be smart about this.
Note: This deals only with VMAs marked as huge which are allocated by
users through hugetlbfs only. Transparent huge pages can only be
detected by looking at the underlying pages (or the page tables
themselves) and this patch so far simply maps these on a page-by-page
level in the Stage-2 page tables.
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Russell King <rmk+kernel@arm.linux.org.uk>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
