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* lguest, x86/entry/32: Fix handling of guest syscalls using interrupt gatesRusty Russell2016-04-011-1/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In a798f091113e ("x86/entry/32: Change INT80 to be an interrupt gate") Andy broke lguest. This is because lguest had special code to allow the 0x80 trap gate go straight into the guest itself; interrupts gates (without more work, as mentioned in the file's comments) bounce via the hypervisor. His change made them go via the hypervisor, but as it's in the range of normal hardware interrupts, they were not directed through to the guest at all. Turns out the guest userspace isn't very effective if syscalls are all noops. I haven't ripped out all the now-useless trap-direct-to-guest-kernel code yet, since it will still be needed if someone decides to update this optimization. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Weisbecker <fweisbec@gmail.com> Cc: x86\@kernel.org Link: http://lkml.kernel.org/r/87fuv685kl.fsf@rustcorp.com.au Signed-off-by: Ingo Molnar <mingo@kernel.org>
* x86/asm/entry: Fix remaining use of SYSCALL_VECTORIngo Molnar2015-05-111-5/+5
| | | | | | | | | | | | | | | | | | | | | Commit: 51bb92843edc ("x86/asm/entry: Remove SYSCALL_VECTOR") Converted most uses of SYSCALL_VECTOR to IA32_SYSCALL_VECTOR, but forgot about lguest. Cc: Brian Gerst <brgerst@gmail.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1431185813-15413-4-git-send-email-brgerst@gmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* lguest: handle traps on the "interrupt suppressed" iret instruction.Rusty Russell2015-04-011-27/+72
| | | | | | | | | | | | | | Lguest's "iret" is non-atomic, as it needs to restore the interrupt state before the real iret (the guest can't actually suppress interrupts). For this reason, the host discards an interrupt if it occurs in this (1-instruction) window. We can do better, by emulating the iret execution, then immediately setting up the interrupt handler. In fact, we don't need to do much, as emulating the iret and setting up th stack for the interrupt handler basically cancel each other out. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* lguest: suppress interrupts for single insn, not range.Rusty Russell2015-03-241-4/+4
| | | | | | | | | | The last patch reduced our interrupt-suppression region to one address, so simplify the code somewhat. Also, remove the obsolete undefined instruction ranges and the comment which refers to lguest_guest.S instead of head_32.S. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* lguest: fix guest kernel stack overflow when TF bit set.Rusty Russell2013-09-061-0/+10
| | | | | | | | | The symptoms are that running gdb on a binary causes the guest to overflow the kernels stack (after some period of time), resulting in it finally being killed with a "Bad address" message. Reported-by: Sakari Ailus <sakari.ailus@iki.fi> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* lguest: update commentsRusty Russell2011-07-221-2/+2
| | | | | | Also removes a long-unused #define and an extraneous semicolon. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* lguest: don't rewrite vmcall instructionsRusty Russell2011-07-221-4/+2
| | | | | | Now we no longer use vmcall, we don't need to rewrite it in the Guest. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* headers: remove sched.h from interrupt.hAlexey Dobriyan2009-10-111-0/+1
| | | | | | | | After m68k's task_thread_info() doesn't refer to current, it's possible to remove sched.h from interrupt.h and not break m68k! Many thanks to Heiko Carstens for allowing this. Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
* lguest: fix comment styleRusty Russell2009-07-301-97/+191
| | | | | | | | | 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: allow any process to send interruptsRusty Russell2009-06-121-4/+15
| | | | | | | | | | | We currently only allow the Launcher process to send interrupts, but it as we already send interrupts from the hrtimer, it's a simple matter of extracting that code into a common set_interrupt routine. As we switch to a thread per virtqueue, this avoids a bottleneck through the main Launcher process. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* lguest: improve interrupt handling, speed up stream networkingRusty Russell2009-06-121-3/+13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | 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: fix race in halt codeRusty Russell2009-06-121-9/+17
| | | | | | | | | | | | | When the Guest does the LHCALL_HALT hypercall, we go to sleep, expecting that a timer or the Waker will wake_up_process() us. But we do it in a stupid way, leaving a classic missing wakeup race. So split maybe_do_interrupt() into interrupt_pending() and try_deliver_interrupt(), and check maybe_do_interrupt() and the "break_out" flag before calling schedule. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* lguest: fix lguest wake on guest clock tick, or fd activityRusty Russell2009-06-121-3/+3
| | | | | | | | | The Launcher could be inside the Guest on another CPU; wake_up_process will do nothing because it is "running". kick_process will knock it back into our kernel in this case, otherwise we'll miss it until the next guest exit. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* lguest: use bool instead of intMatias Zabaljauregui2009-03-301-10/+11
| | | | | | | | | | Impact: clean up Rusty told me, some time ago, that he had become a fan of "bool". So, here are some replacements. Signed-off-by: Matias Zabaljauregui <zabaljauregui at gmail.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* lguest: use KVM hypercallsMatias Zabaljauregui2009-03-301-3/+4
| | | | | | | | | 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>
* x86: fix lguest used_vectors breakage, -v2Yinghai Lu2008-12-231-4/+9
| | | | | | | | | | | | | | | | | | | | | Impact: fix lguest, clean up 32-bit lguest used used_vectors to record vectors, but that model of allocating vectors changed and got broken, after we changed vector allocation to a per_cpu array. Try enable that for 64bit, and the array is used for all vectors that are not managed by vector_irq per_cpu array. Also kill system_vectors[], that is now a duplication of the used_vectors bitmap. [ merged in cpus4096 due to io_apic.c cpumask changes. ] [ -v2, fix build failure ] Signed-off-by: Yinghai Lu <yinghai@kernel.org> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* lguest: Guest int3 fixRusty Russell2008-07-291-7/+17
| | | | | | | | | Ron Minnich noticed that guest userspace gets a GPF when it tries to int3: we need to copy the privilege level from the guest-supplied IDT to the real IDT. int3 is the only common case where guest userspace expects to invoke an interrupt, so that's the symptom of failing to do this. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* lguest: comment documentation update.Rusty Russell2008-03-281-4/+3
| | | | | | | | | 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: get rid of lg variable assignmentsGlauber de Oliveira Costa2008-01-301-28/+26
| | | | | | | | We can save some lines of code by getting rid of *lg = cpu... lines of code spread everywhere by now. Signed-off-by: Glauber de Oliveira Costa <gcosta@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* lguest: move changed bitmap to lg_cpuGlauber de Oliveira Costa2008-01-301-1/+1
| | | | | | | | events represented in the 'changed' bitmap are per-cpu, not per-guest. move it to the lg_cpu structure Signed-off-by: Glauber de Oliveira Costa <gcosta@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* lguest: per-vcpu lguest pgdir managementGlauber de Oliveira Costa2008-01-301-3/+3
| | | | | | | | | | | this patch makes the pgdir management per-vcpu. The pgdirs pool is still guest-wide (although it'll probably need to grow when we are really executing more vcpus), but the pgdidx index is gone, since it makes no sense anymore. Instead, we use a per-vcpu index. Signed-off-by: Glauber de Oliveira Costa <gcosta@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* lguest: makes special fields be per-vcpuGlauber de Oliveira Costa2008-01-301-11/+12
| | | | | | | | | | lguest struct have room for some fields, namely, cr2, ts, esp1 and ss1, that are not really guest-wide, but rather, vcpu-wide. This patch puts it in the vcpu struct Signed-off-by: Glauber de Oliveira Costa <gcosta@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* lguest: per-vcpu lguest task managementGlauber de Oliveira Costa2008-01-301-4/+4
| | | | | | | | | | lguest uses tasks to control its running behaviour (like sending breaks, controlling halted state, etc). In a per-vcpu environment, each vcpu will have its own underlying task. So this patch makes the infrastructure for that possible Signed-off-by: Glauber de Oliveira Costa <gcosta@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* lguest: replace lguest_arch with lg_cpu_arch.Glauber de Oliveira Costa2008-01-301-14/+14
| | | | | | | | | | | | The fields found in lguest_arch are not really per-guest, but per-cpu (gdt, idt, etc). So this patch turns lguest_arch into lg_cpu_arch. It makes sense to have a per-guest per-arch struct, but this can be addressed later, when the need arrives. Signed-off-by: Glauber de Oliveira Costa <gcosta@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* lguest: make registers per-vcpuGlauber de Oliveira Costa2008-01-301-14/+14
| | | | | | | | | | This is the most obvious per-vcpu field: registers. So this patch moves it from struct lguest to struct vcpu, and patch the places in which they are used, accordingly Signed-off-by: Glauber de Oliveira Costa <gcosta@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* lguest: per-vcpu interrupt processing.Glauber de Oliveira Costa2008-01-301-11/+13
| | | | | | | This patch adapts interrupt processing for using the vcpu struct. Signed-off-by: Glauber de Oliveira Costa <gcosta@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* lguest: per-vcpu lguest timersGlauber de Oliveira Costa2008-01-301-10/+10
| | | | | | | | Here, I introduce per-vcpu timers. With this, we can have local expiries, needed for accounting time in smp guests Signed-off-by: Glauber de Oliveira Costa <gcosta@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* lguest: documentation updateRusty Russell2007-10-251-8/+29
| | | | | | | | 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>
* generalize lgread_u32/lgwrite_u32.Rusty Russell2007-10-231-1/+1
| | | | | | | | | | | | | | Jes complains that page table code still uses lgread_u32 even though it now uses general kernel pte types. The best thing to do is to generalize lgread_u32 and lgwrite_u32. This means we lose the efficiency of getuser(). We could potentially regain it if we used __copy_from_user instead of copy_from_user, but I'm not certain that our range check is equivalent to access_ok() on all platforms. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Acked-by: Jes Sorensen <jes@sgi.com>
* Boot with virtual == physical to get closer to native Linux.Rusty Russell2007-10-231-4/+9
| | | | | | | | | | | | | | | | | | | | 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 Russell2007-10-231-1/+48
| | | | | | | | | | (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>
* Move i386 part of core.c to x86/core.c.Jes Sorensen2007-10-231-9/+9
| | | | | | | | Separate i386 architecture specific from core.c and move it to x86/core.c and add x86/lguest.h header file to match. Signed-off-by: Jes Sorensen <jes@sgi.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* Make shadow IDT a complete IDT with 256 entries.Rusty Russell2007-10-231-30/+19
| | | | | | | This simplifies the code a little, in preparation for allowing alternate system call vectors in guests (Plan 9 uses 0x40). Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* Fix lguest page-pinning logic ("lguest: bad stack page 0xc057a000")Rusty Russell2007-08-301-2/+5
| | | | | | | | | | | | | | If the stack pointer is 0xc057a000, then the first stack page is at 0xc0579000 (the stack pointer is decremented before use). Not calculating this correctly caused guests with CONFIG_DEBUG_PAGEALLOC=y to be killed with a "bad stack page" message: the initial kernel stack was just proceeding the .smp_locks section which CONFIG_DEBUG_PAGEALLOC marks read-only when freeing. Thanks to Frederik Deweerdt for the bug report! Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* lguest: Fix Malicious Guest GDT Host CrashRusty Russell2007-08-091-3/+6
| | | | | | | | | | | | | | | | | | | If a Guest makes hypercall which sets a GDT entry to not present, we currently set any segment registers using that GDT entry to 0. Unfortunately, this is not sufficient: there are other ways of altering GDT entries which will cause a fault. The correct solution to do what Linux does: let them set any GDT value they want and handle the #GP when popping causes a fault. This has the added benefit of making our Switcher slightly more robust in the case of any other bugs which cause it to fault. We kill the Guest if it causes a fault in the Switcher: it's the Guest's responsibility to make sure it's not using segments when it changes them. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Provide timespec to guests rather than jiffies clock.Rusty Russell2007-07-281-0/+7
| | | | | | | | | | | | | | | | | 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 VII: FIXMEsRusty Russell2007-07-261-0/+14
| | | | | | | | Documentation: The FIXMEs 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: documentation V: HostRusty Russell2007-07-261-19/+157
| | | | | | | | Documentation: The Host 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: documentation I: PreparationRusty Russell2007-07-261-0/+13
| | | | | | | | | | | The netfilter code had very good documentation: the Netfilter Hacking HOWTO. Noone ever read it. So this time I'm trying something different, using a bit of Knuthiness. 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: fix sense if IF flag on interrupt injectionRusty Russell2007-07-201-5/+5
| | | | | | | | | | | | The sense of the IF bit is backwards in the host interrupt handling. This means we always save "IF=1" on the stack when injecting an interrupt. It turns out this is almost always correct (unless the guest is taking a page fault in an interrupt due to an unpopulated vmalloc mapping), so went unnoticed. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* lguest: the host codeRusty Russell2007-07-191-0/+268
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>
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