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| author | Rusty Russell <rusty@rustcorp.com.au> | 2011-07-22 14:39:48 +0930 |
|---|---|---|
| committer | Rusty Russell <rusty@rustcorp.com.au> | 2011-07-22 14:39:48 +0930 |
| commit | 5dea1c88ed11a1221581c4b202f053c4fc138704 (patch) | |
| tree | 59e15d3c696712e26ffb229ff987f33bcc72affe /include/linux/lguest.h | |
| parent | e0377e25206328998d036cafddcd00a7c3252e3e (diff) | |
| download | lwn-5dea1c88ed11a1221581c4b202f053c4fc138704.tar.gz lwn-5dea1c88ed11a1221581c4b202f053c4fc138704.zip | |
lguest: use a special 1:1 linear pagetable mode until first switch.
The Host used to create some page tables for the Guest to use at the
top of Guest memory; it would then tell the Guest where this was. In
particular, it created linear mappings for 0 and 0xC0000000 addresses
because lguest used to switch to its real page tables quite late in
boot.
However, since d50d8fe19 Linux initialized boot page tables in
head_32.S even before the "are we lguest?" boot jump. So, now we can
simplify things: the Host pagetable code assumes 1:1 linear mapping
until it first calls the LHCALL_NEW_PGTABLE hypercall, which we now do
before we reach C code.
This also means that the Host doesn't need to know anything about the
Guest's PAGE_OFFSET. (Non-Linux guests might not even have such a
thing).
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Diffstat (limited to 'include/linux/lguest.h')
| -rw-r--r-- | include/linux/lguest.h | 2 |
1 files changed, 0 insertions, 2 deletions
diff --git a/include/linux/lguest.h b/include/linux/lguest.h index 2fb1dcbcb5aa..9962c6bb1311 100644 --- a/include/linux/lguest.h +++ b/include/linux/lguest.h @@ -59,8 +59,6 @@ struct lguest_data { unsigned long reserve_mem; /* KHz for the TSC clock. */ u32 tsc_khz; - /* Page where the top-level pagetable is */ - unsigned long pgdir; /* Fields initialized by the Guest at boot: */ /* Instruction range to suppress interrupts even if enabled */ |