booter: build a self-owned LINEAR TLB for the bootvm ASID - #81
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Bryan Bayerdorffer (bryanb-h2)
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Did you look at add_linear_trans() to see if it could be repurposed for this? |
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Neeraj Jetha (njjetha)
July 27, 2026 14:27
Replace the kernel's OFFSET translation with a LINEAR table the booter builds and installs itself via h2_vmtrap_newmap(), covering its own footprint (image + heap + stack) sized from BOOT_TLB_PGSIZE and PAGE_BITS. Add a GUEST_WINDOW_PAGES-sized (16M-page) window starting at H2K_GUEST_START, since load_vm() accesses guest physical memory directly through the booter's own map and needs coverage beyond the booter's footprint entries. Signed-off-by: Tzahi Sabo <stzahi@qti.qualcomm.com>
…xed guess booter_self_map() used to install a fixed GUEST_WINDOW_PAGES (5 x 16M) guest window before any guest ELF was even opened, silently capping how much guest memory the booter could read/write directly via load_vm()/ copy_vm(). Move that mapping into load_vm() itself, growing the booter's persistent LINEAR table on demand (booter_grow_guest_window()) at each point where the actual required size becomes known: the phdr load loop, the clone-path copy_vm(), and the stash-path copy_vm(). Window growth is sized per-VM using vm_params[idx].page_size instead of a hardcoded constant. booter_self_map() now builds footprint-only entries; GUEST_WINDOW_PAGES is removed. Signed-off-by: Tzahi Sabo <stzahi@qti.qualcomm.com>
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guest_base + pre_total_size was computed in 32-bit arithmetic before being passed to booter_grow_guest_window()'s unsigned long long parameter. For high guest_base values (e.g. opt_si's 0x87000000) the addition could wrap, silently under-growing or no-op'ing the guest LINEAR window instead of sizing it correctly. Signed-off-by: Tzahi Sabo <stzahi@qti.qualcomm.com>
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Replace the kernel's OFFSET translation with a LINEAR table the booter builds and installs itself via h2_vmtrap_newmap(), covering its own footprint (image + heap + stack) sized from BOOT_TLB_PGSIZE and PAGE_BITS.
Add a GUEST_WINDOW_PAGES-sized (16M-page) window starting at H2K_GUEST_START, since load_vm() accesses guest physical memory directly through the booter's own map and needs coverage beyond the booter's footprint entries.