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* lguest: use a special 1:1 linear pagetable mode until first switch.Rusty Russell2011-07-221-2/+0
| | | | | | | | | | | | | | | | | | | | 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>
* lguest and virtio: cleanup struct definitions to Linux style.Rusty Russell2009-07-301-2/+1
| | | | | | | | | | I've been doing this for years, and akpm picked me up on it about 12 months ago. lguest partly serves as example code, so let's do it Right. Also, remove two unused fields in struct vblk_info in the example launcher. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Cc: Ingo Molnar <mingo@redhat.com>
* lguest: fix comment styleRusty Russell2009-07-301-12/+24
| | | | | | | | | 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: fix journeyMatias Zabaljauregui2009-07-171-1/+1
| | | | | | | fix: "make Guest" was complaining about duplicated G:032 Signed-off-by: Matias Zabaljauregui <zabaljauregui@gmail.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* lguest: improve interrupt handling, speed up stream networkingRusty Russell2009-06-121-0/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | 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: documentation updateRusty Russell2007-10-251-2/+2
| | | | | | | | 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>
* Boot with virtual == physical to get closer to native Linux.Rusty Russell2007-10-231-1/+4
| | | | | | | | | | | | | | | | | | | | 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>
* Allow guest to specify syscall vector to use.Rusty Russell2007-10-231-0/+3
| | | | | | | | | | (Based on Ron Minnich's LGUEST_PLAN9_SYSCALL patch). This patch allows Guests to specify what system call vector they want, and we try to reserve it. We only allow one non-Linux system call vector, to try to avoid DoS on the Host. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* lguest.h declares a struct timespec, make it include linux/time.hJes Sorensen2007-10-231-0/+1
| | | | | Signed-off-by: Jes Sorensen <jes@sgi.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* Make hypercalls arch-independent.Jes Sorensen2007-10-231-1/+1
| | | | | | | | | | | | | | Clean up the hypercall code to make the code in hypercalls.c architecture independent. First process the common hypercalls and then call lguest_arch_do_hcall() if the call hasn't been handled. Rename struct hcall_ring to hcall_args. This patch requires the previous patch which reorganize the layout of struct lguest_regs on i386 so they match the layout of struct hcall_args. Signed-off-by: Jes Sorensen <jes@sgi.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* Remove fixed limit on number of guests, and lguests array.Rusty Russell2007-10-231-2/+0
| | | | | | | | | | | Back when we had all the Guest state in the switcher, we had a fixed array of them. This is no longer necessary. If we switch the network code to using random_ether_addr (46 bits is enough to avoid clashes), we can get rid of the concept of "guest id" altogether. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* Move lguest hcalls to arch-specific headerJes Sorensen2007-10-231-65/+4
| | | | | | | | | | | Move architecture specific portion of lg_hcall code to asm-i386/lg_hcall.h and have it included from linux/lguest.h. [Changed to asm-i386/lguest_hcall.h so documentation finds it -RR] Signed-off-by: Jes Sorensen <jes@sgi.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Cc: Jes Sorensen <jes@sgi.com>
* Provide timespec to guests rather than jiffies clock.Rusty Russell2007-07-281-1/+3
| | | | | | | | | | | | | | | | | A non-periodic clock_event_device and the "jiffies" clock don't mix well: tick_handle_periodic() can go into an infinite loop. Currently lguest guests use the jiffies clock when the TSC is unusable. Instead, make the Host write the current time into the lguest page on every interrupt. This doesn't cost much but is more precise and at least as accurate as the jiffies clock. It also gets rid of the GET_WALLCLOCK hypercall. Also, delay setting sched_clock until our clock is set up, otherwise the early printk timestamps can go backwards (not harmful, just ugly). Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* lguest: documentation II: GuestRusty Russell2007-07-261-9/+38
| | | | | | | | Documentation: The Guest Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* lguest: the host codeRusty Russell2007-07-191-6/+6
| | | | | | | | | | | | | | | | This is the code for the "lg.ko" module, which allows lguest guests to be launched. [akpm@linux-foundation.org: update for futex-new-private-futexes] [akpm@linux-foundation.org: build fix] [jmorris@namei.org: lguest: use hrtimers] [akpm@linux-foundation.org: x86_64 build fix] Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Cc: Andi Kleen <ak@suse.de> Cc: Eric Dumazet <dada1@cosmosbay.com> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* lguest: the guest codeRusty Russell2007-07-191-0/+85
lguest is a simple hypervisor for Linux on Linux. Unlike kvm it doesn't need VT/SVM hardware. Unlike Xen it's simply "modprobe and go". Unlike both, it's 5000 lines and self-contained. Performance is ok, but not great (-30% on kernel compile). But given its hackability, I expect this to improve, along with the paravirt_ops code which it supplies a complete example for. There's also a 64-bit version being worked on and other craziness. But most of all, lguest is awesome fun! Too much of the kernel is a big ball of hair. lguest is simple enough to dive into and hack, plus has some warts which scream "fork me!". This patch: This is the code and headers required to make an i386 kernel an lguest guest. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Cc: Andi Kleen <ak@suse.de> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>