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* lguest: Fix three simple typos in commentsAdrian Knoth2011-07-221-1/+1
| | | | | | | This patch fixes three typos I've accidentally spotted. Signed-off-by: Adrian Knoth <adi@drcomp.erfurt.thur.de> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> (one was already fixed)
* lguest: update commentsRusty Russell2011-07-221-7/+11
| | | | | | Also removes a long-unused #define and an extraneous semicolon. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* lguest: remove remaining vmcallRusty Russell2011-07-221-6/+2
| | | | | | | We switch back from using vmcall in 091ebf07a2408f9a56634caa0f86d9360e9af23b because it was unreliable under kvm, but I missed one (rarely-used) place. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* lguest: use a special 1:1 linear pagetable mode until first switch.Rusty Russell2011-07-221-2/+7
| | | | | | | | | | | | | | | | | | | | 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>
* x86, mm: Initialize initial_page_table before paravirt jumpsRusty Russell2011-01-041-105/+0
| | | | | | | | | | | | | | | | | | | | v2.6.36-rc8-54-gb40827f (x86-32, mm: Add an initial page table for core bootstrapping) made x86 boot using initial_page_table and broke lguest. For 2.6.37 we simply cut & paste the initialization code into lguest (da32dac10126 "lguest: populate initial_page_table"), now we fix it properly by doing that initialization before the paravirt jump. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Acked-by: Jeremy Fitzhardinge <jeremy@goop.org> Cc: lguest <lguest@ozlabs.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <201101041720.54535.rusty@rustcorp.com.au> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* lguest: populate initial_page_tableRusty Russell2010-12-161-0/+105
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Two x86 patches broke lguest: 1) v2.6.35-492-g72d7c3b, which changed x86 to use the memblock allocator. In lguest, the host places linear page tables at the top of mem, which used to be enough to get us up to the swapper_pg_dir page tables. With the first patch, the direct mapping tables used that memory: Before: kernel direct mapping tables up to 4000000 @ 7000-1a000 After: kernel direct mapping tables up to 4000000 @ 3fed000-4000000 I initially fixed this by lying about the amount of memory we had, so the kernel wouldn't blatt the lguest boot pagetables (yuk!), but then... 2) v2.6.36-rc8-54-gb40827f, which made x86 boot use initial_page_table. This was initialized in a part of head_32.S which isn't executed by lguest; it is then copied into swapper_pg_dir. So we have to initialize it; and anyway we switch to it before we blatt the old tables, so that fixes the previous damage as well. For the moment, I cut & pasted the code into lguest's boot code, but next merge window I will merge them. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Cc: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> To: x86@kernel.org
* lguest: stop using KVM hypercall mechanismRusty Russell2010-04-141-1/+1
| | | | | | | | | | | | | | | | This is a partial revert of 4cd8b5e2a159 "lguest: use KVM hypercalls"; we revert to using (just as questionable but more reliable) int $15 for hypercalls. I didn't revert the register mapping, so we still use the same calling convention as kvm. KVM in more recent incarnations stopped injecting a fault when a guest tried to use the VMCALL instruction from ring 1, so lguest under kvm fails to make hypercalls. It was nice to share code with our KVM cousins, but this was overreach. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Cc: Matias Zabaljauregui <zabaljauregui@gmail.com> Cc: Avi Kivity <avi@redhat.com>
* lguest: update commentryRusty Russell2009-07-301-0/+2
| | | | | | | | | | Every so often, after code shuffles, I need to go through and unbitrot the Lguest Journey (see drivers/lguest/README). Since we now use RCU in a simple form in one place I took the opportunity to expand that explanation. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Cc: Ingo Molnar <mingo@redhat.com> Cc: Paul McKenney <paulmck@linux.vnet.ibm.com>
* lguest: fix comment styleRusty Russell2009-07-301-42/+68
| | | | | | | | | I don't really notice it (except to begrudge the extra vertical space), but Ingo does. And he pointed out that one excuse of lguest is as a teaching tool, it should set a good example. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Cc: Ingo Molnar <mingo@redhat.com>
* lguest: optimize by coding restore_flags and irq_enable in assembler.Rusty Russell2009-06-121-1/+57
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The downside of the last patch which made restore_flags and irq_enable check interrupts is that they are now too big to be patched directly into the callsites, so the C versions are always used. But the C versions go via PV_CALLEE_SAVE_REGS_THUNK which saves all the registers. In fact, we don't need any registers in the fast path, so we can do better than this if we actually code them in assembler. The results are in the noise, but since it's about the same amount of code, it's worth applying. 1GB Guest->Host: input(suppressed),output(suppressed) Before: Seconds: 0:16.53 Packets: 377268,753673 Interrupts: 22461,24297 Notifications: 1(5245),21303(732370) Net IRQs triggered: 377023(245),42578(711095) After: Seconds: 0:16.48 Packets: 377289,753673 Interrupts: 22281,24465 Notifications: 1(5245),21296(732377) Net IRQs triggered: 377060(229),42564(711109) Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* lguest: improve interrupt handling, speed up stream networkingRusty Russell2009-06-121-2/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | lguest never checked for pending interrupts when enabling interrupts, and things still worked. However, it makes a significant difference to TCP performance, so it's time we fixed it by introducing a pending_irq flag and checking it on irq_restore and irq_enable. These two routines are now too big to patch into the 8/10 bytes patch space, so we drop that code. Note: The high latency on interrupt delivery had a very curious effect: once everything else was optimized, networking without GSO was faster than networking with GSO, since more interrupts were sent and hence a greater chance of one getting through to the Guest! Note2: (Almost) Closing the same loophole for iret doesn't have any measurable effect, so I'm leaving that patch for the moment. Before: 1GB tcpblast Guest->Host: 30.7 seconds 1GB tcpblast Guest->Host (no GSO): 76.0 seconds After: 1GB tcpblast Guest->Host: 6.8 seconds 1GB tcpblast Guest->Host (no GSO): 27.8 seconds Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* lguest: use KVM hypercallsMatias Zabaljauregui2009-03-301-2/+2
| | | | | | | | | Impact: cleanup This patch allow us to use KVM hypercalls Signed-off-by: Matias Zabaljauregui <zabaljauregui at gmail.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* lguest: move the initial guest page table creation code to the hostMatias Zabaljauregui2008-12-301-15/+0
| | | | | | | | This patch moves the initial guest page table creation code to the host, so the launcher keeps working with PAE enabled configs. Signed-off-by: Matias Zabaljauregui <zabaljauregui@gmail.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* lguest: comment documentation update.Rusty Russell2008-03-281-4/+11
| | | | | | | | | Took some cycles to re-read the Lguest Journey end-to-end, fix some rot and tighten some phrases. Only comments change. No new jokes, but a couple of recycled old jokes. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* lguest: documentation updateRusty Russell2007-10-251-3/+5
| | | | | | | | Went through the documentation doing typo and content fixes. This patch contains only comment and whitespace changes. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* Revert lguest magic and use hook in head.SRusty Russell2007-10-231-13/+4
| | | | | | | | | | | Version 2.07 of the boot protocol uses 0x23C for the hardware_subarch field, that for lguest is "1". This allows us to use the standard boot entry point rather than the "GenuineLguest" string hack. The standard entry point also clears the BSS and copies the boot parameters and commandline for us, saving more code. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* Boot with virtual == physical to get closer to native Linux.Rusty Russell2007-10-231-5/+36
| | | | | | | | | | | | | | | | | | | | 1) This allows us to get alot closer to booting bzImages. 2) It means we don't have to know page_offset. 3) The Guest needs to modify the boot pagetables to create the PAGE_OFFSET mapping before jumping to C code. 4) guest_pa() walks the page tables rather than using page_offset. 5) We don't use page_offset to figure out whether to emulate: it was always kinda quesationable, and won't work for instructions done before remapping (bzImage unpacking in particular). 6) We still want the kernel address for tlb flushing: have the initial hypercall give us that, too. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* Move lguest guest support to arch/x86.Rusty Russell2007-10-231-0/+93
Lguest has two sides: host support (to launch guests) and guest support (replacement boot path and paravirt_ops). This moves the guest side to arch/x86/lguest where it's closer to related code. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Cc: Andi Kleen <ak@suse.de>
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