get_page_from_l1e() relied on Xen's choice of PAT, which is brittle in
the face of future PAT changes. Instead, compute the actual cacheability
used by the CPU and switch on that, as this will work no matter what PAT
Xen uses.
No functional change intended. This code is itself questionable and may
be removed in the future, but removing it would be an observable
behavior change and so is out of scope for this patch series.
Signed-off-by: Demi Marie Obenour <demi@invisiblethingslab.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
This avoids it being a magic constant that is difficult for humans to
decode. Use BUILD_BUG_ON to check that the old and new values are
identical.
Signed-off-by: Demi Marie Obenour <demi@invisiblethingslab.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
This allows eliminating of the former, with the exception of
MTRR_NUM_TYPES. MTRR_NUM_TYPES is kept, as due to a quirk of the x86
architecture X86_MT_UCM (7) is not valid in an MTRR.
Suggested-by: Andrew Cooper <andrew.cooper3@citrix.com>
Signed-off-by: Demi Marie Obenour <demi@invisiblethingslab.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
This makes the code much easier to understand, and avoids problems if
Xen's PAT ever changes in the future.
Signed-off-by: Demi Marie Obenour <demi@invisiblethingslab.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
This makes the code much easier to understand. No functional change
intended. As per Andrew Cooper, the existing logic is questionable, but
this does not make it any worse.
Signed-off-by: Demi Marie Obenour <demi@invisiblethingslab.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
This was missed in the initial patchset.
Move efi_relocate_esrt() up to avoid adding a forward declaration.
Signed-off-by: Demi Marie Obenour <demi@invisiblethingslab.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
A previous patch tried to get Linux to use the ESRT under Xen if it is
in memory of type EfiRuntimeServicesData. However, this turns out to be
a bad idea. Ard Biesheuvel pointed out that EfiRuntimeServices* memory
winds up fragmenting both the EFI page tables and the direct map, and
that EfiACPIReclaimMemory is a much better choice for this purpose.
Link: https://lists.xenproject.org/archives/html/xen-devel/2022-09/msg01365.html
Signed-off-by: Demi Marie Obenour <demi@invisiblethingslab.com>
Release-acked-by: Henry Wang <Henry.Wang@arm.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
The EFI System Resource Table (ESRT) is necessary for fwupd to identify
firmware updates to install. According to the UEFI specification §23.4,
the ESRT shall be stored in memory of type EfiBootServicesData. However,
memory of type EfiBootServicesData is considered general-purpose memory
by Xen, so the ESRT needs to be moved somewhere where Xen will not
overwrite it. Copy the ESRT to memory of type EfiRuntimeServicesData,
which Xen will not reuse. dom0 can use the ESRT if (and only if) it is
in memory of type EfiRuntimeServicesData.
Earlier versions of this patch reserved the memory in which the ESRT was
located. This created awkward alignment problems, and required either
splitting the E820 table or wasting memory. It also would have required
a new platform op for dom0 to use to indicate if the ESRT is reserved.
By copying the ESRT into EfiRuntimeServicesData memory, the E820 table
does not need to be modified, and dom0 can just check the type of the
memory region containing the ESRT. The copy is only done if the ESRT is
not already in EfiRuntimeServicesData memory, avoiding memory leaks on
repeated kexec.
See https://lore.kernel.org/xen-devel/20200818184018.GN1679@mail-itl/T/
for details.
Signed-off-by: Demi Marie Obenour <demi@invisiblethingslab.com>
Tested-by: Luca Fancellu <luca.fancellu@arm.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
The EFI System Resource Table (ESRT) is necessary for fwupd to identify
firmware updates to install. According to the UEFI specification §23.4,
the ESRT shall be stored in memory of type EfiBootServicesData. However,
memory of type EfiBootServicesData is considered general-purpose memory
by Xen, so the ESRT needs to be moved somewhere where Xen will not
overwrite it. Copy the ESRT to memory of type EfiRuntimeServicesData,
which Xen will not reuse. dom0 can use the ESRT if (and only if) it is
in memory of type EfiRuntimeServicesData.
Earlier versions of this patch reserved the memory in which the ESRT was
located. This created awkward alignment problems, and required either
splitting the E820 table or wasting memory. It also would have required
a new platform op for dom0 to use to indicate if the ESRT is reserved.
By copying the ESRT into EfiRuntimeServicesData memory, the E820 table
does not need to be modified, and dom0 can just check the type of the
memory region containing the ESRT. The copy is only done if the ESRT is
not already in EfiRuntimeServicesData memory, avoiding memory leaks on
repeated kexec.
See https://lore.kernel.org/xen-devel/20200818184018.GN1679@mail-itl/T/
for details.
Signed-off-by: Demi Marie Obenour <demi@invisiblethingslab.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Demi Marie Obenour