ppc64: Avoid restricted memory areas when allocating memory #152
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The regions_claim() function limits the allocation of memory regions by excluding certain memory areas from being used by GRUB. This for example includes a gap between 640MB and 768MB as well as an upper limit beyond which no memory may be used when an fadump is present. However, the ieee1275 loader for kernel and initrd currently does not use regions_claim() for memory allocation on PowerVM and KVM on Power and therefore may allocate memory in those areas that it should not use. To make the regions_claim() function more flexible and ultimately usable for the ieee1275 loader, introduce a request structure to pass various parameters to the regions_claim() function that describe the properties of requested memory chunks. In a first step, move the total and flags variables into this structure. Signed-off-by: Stefan Berger <[email protected]> Reviewed-by: Daniel Kiper <[email protected]> Cc: Hari Bathini <[email protected]> Cc: Pavithra Prakash <[email protected]> Cc: Michael Ellerman <[email protected]> Cc: Carolyn Scherrer <[email protected]> Cc: Mahesh Salgaonkar <[email protected]> Cc: Sourabh Jain <[email protected]>
Let the regions_claim() request structure's init_region determine whether to call grub_mm_init_region() on it. This allows for adding memory to GRUB's memory heap if init_region is set to true, or direct usage of the memory otherwise. Set all current callers' init_region to true since they want to add memory regions to GRUB's heap. Signed-off-by: Stefan Berger <[email protected]> Reviewed-by: Daniel Kiper <[email protected]> Cc: Hari Bathini <[email protected]> Cc: Pavithra Prakash <[email protected]> Cc: Michael Ellerman <[email protected]> Cc: Carolyn Scherrer <[email protected]> Cc: Mahesh Salgaonkar <[email protected]> Cc: Sourabh Jain <[email protected]>
Return the allocated address of the memory block in the request structure if a memory allocation was actually done. Leave the address untouched otherwise. This enables a caller who wants to use the allocated memory directly, rather than adding the memory to the heap, to see where memory was allocated. None of the current callers need this but the converted ieee1275 loader will make use of it. Signed-off-by: Stefan Berger <[email protected]> Reviewed-by: Daniel Kiper <[email protected]> Cc: Hari Bathini <[email protected]> Cc: Pavithra Prakash <[email protected]> Cc: Michael Ellerman <[email protected]> Cc: Carolyn Scherrer <[email protected]> Cc: Mahesh Salgaonkar <[email protected]> Cc: Sourabh Jain <[email protected]>
Add support for memory alignment requirements and adjust a candidate address to it before checking whether the block is large enough. This must be done in this order since the alignment adjustment can make a block smaller than what was requested. None of the current callers has memory alignment requirements but the ieee1275 loader for kernel and initrd will use it to convey them. Signed-off-by: Stefan Berger <[email protected]> Reviewed-by: Daniel Kiper <[email protected]> Cc: Hari Bathini <[email protected]> Cc: Pavithra Prakash <[email protected]> Cc: Michael Ellerman <[email protected]> Cc: Carolyn Scherrer <[email protected]> Cc: Mahesh Salgaonkar <[email protected]> Cc: Sourabh Jain <[email protected]>
Rename regions_claim() to grub_regions_claim() to make it available for memory allocation. The ieee1275 loader will use this function on PowerVM and KVM on Power and thus avoid usage of memory that it is not allowed to use. Signed-off-by: Stefan Berger <[email protected]> Reviewed-by: Daniel Kiper <[email protected]> Cc: Hari Bathini <[email protected]> Cc: Pavithra Prakash <[email protected]> Cc: Michael Ellerman <[email protected]> Cc: Carolyn Scherrer <[email protected]> Cc: Mahesh Salgaonkar <[email protected]> Cc: Sourabh Jain <[email protected]>
Introduce flags to identify PowerVM and KVM on Power and set them where each type of host has been detected. Signed-off-by: Stefan Berger <[email protected]> Reviewed-by: Daniel Kiper <[email protected]> Cc: Hari Bathini <[email protected]> Cc: Pavithra Prakash <[email protected]> Cc: Michael Ellerman <[email protected]> Cc: Carolyn Scherrer <[email protected]> Cc: Mahesh Salgaonkar <[email protected]> Cc: Sourabh Jain <[email protected]>
…nitrd On PowerVM and KVM on Power use the new memory allocation function that honors restrictions on which memory GRUB can actually use. In the request structure indicate the request for a single memory block along with address alignment restrictions. Request direct usage of the memory block by setting init_region to false (prevent it from being added to GRUB's heap). Initialize the found addr to -1, so that -1 will be returned to the loader in case no memory could be allocated. Report an out-of-memory error in case the initrd could not be loaded. Signed-off-by: Stefan Berger <[email protected]> Reviewed-by: Daniel Kiper <[email protected]> Cc: Hari Bathini <[email protected]> Cc: Pavithra Prakash <[email protected]> Cc: Michael Ellerman <[email protected]> Cc: Carolyn Scherrer <[email protected]> Cc: Mahesh Salgaonkar <[email protected]> Cc: Sourabh Jain <[email protected]>
Display successful memory claims with exact address and rounded-down MiB location and rounded-up size in MiB. Signed-off-by: Stefan Berger <[email protected]> Reviewed-by: Daniel Kiper <[email protected]> Cc: Eric Snowberg <[email protected]> Cc: Hari Bathini <[email protected]> Cc: Pavithra Prakash <[email protected]> Cc: Michael Ellerman <[email protected]> Cc: Carolyn Scherrer <[email protected]> Cc: Mahesh Salgaonkar <[email protected]> Cc: Sourabh Jain <[email protected]>
Signed-off-by: Stefan Berger <[email protected]> Reviewed-by: Daniel Kiper <[email protected]>
Display upper_mem_limit and its rounded-down value in MiB. Signed-off-by: Stefan Berger <[email protected]> Reviewed-by: Daniel Kiper <[email protected]>
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Hi Stefan, Is this an addendum to 9f0f2df ? |
The patch series avoids having grub touch the memory area 640-768MB, which is supposed to be available for the Linux kernel to allocate initial memory iiuc. In some case it could happen that grub loaded kernel or initrd touching this area.
Let's defer applying this series for now. fadump should also work without it. |
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This is a backport of a recently posted patch series resolving grub memory allocation issues: https://lists.gnu.org/archive/html/grub-devel/2023-11/msg00188.html
This series affects only the memory allocations for kernel and initrd so they don't get placed into 640-768MB region. All other allocations that grub makes have already been 'fixed':
This series of patches converts the PowerPC ieee1275 memory allocator
for kernel and initrd to use the (PowerPC) regions_claim memory allocator
that takes into account memory regions that are not allowed to be used,
such as the gap between 640MB and 768MB as well as memory regions beyond
an address in case an fadump is present. Otherwise those two could be
loaded into restricted memory regions and either cause a crash or
corruption of the fadump.
I adjusted the kernel and initrd load in loader/powerpc/ieee1275 to use
the new memory allocator only on PowerVM and PowerKVM since this code is
shared with other platforms, such as old PowerMACs and i386.
Resolves: https://issues.redhat.com/browse/RHEL-14282