diff options
author | Linus Torvalds | 2015-04-22 10:55:06 -0700 |
---|---|---|
committer | Linus Torvalds | 2015-04-22 10:55:06 -0700 |
commit | b9bb6fb73b3e112d241a5edd146740be9a0c3cc0 (patch) | |
tree | d65072d0371468d685b7464dc6b38f920c0c9666 /arch | |
parent | 15ce2658ddbd3db20dfba3622f3d224f01837fdc (diff) | |
parent | 9abbfb486f5c254805bb6a3f263bc14d989eb90b (diff) |
Merge tag 'virtio-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux
Pull virtio updates from Rusty Russell:
"Some virtio internal cleanups, a new virtio device "virtio input", and
a change to allow the legacy virtio balloon.
Most excitingly, some lguest work! No seriously, I got some cleanup
patches"
* tag 'virtio-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux:
virtio: drop virtio_device_is_legacy_only
virtio_pci: support non-legacy balloon devices
virtio_mmio: support non-legacy balloon devices
virtio_ccw: support non-legacy balloon devices
virtio: balloon might not be a legacy device
virtio_balloon: transitional interface
virtio_ring: Update weak barriers to use dma_wmb/rmb
virtio_pci_modern: switch to type-safe io accessors
virtio_pci_modern: type-safe io accessors
lguest: handle traps on the "interrupt suppressed" iret instruction.
virtio: drop a useless config read
virtio_config: reorder functions
Add virtio-input driver.
lguest: suppress interrupts for single insn, not range.
lguest: simplify lguest_iret
lguest: rename i386_head.S in the comments
lguest: explicitly set miscdevice's private_data NULL
lguest: fix pending interrupt test.
Diffstat (limited to 'arch')
-rw-r--r-- | arch/x86/include/asm/lguest.h | 7 | ||||
-rw-r--r-- | arch/x86/lguest/boot.c | 7 | ||||
-rw-r--r-- | arch/x86/lguest/head_32.S | 30 |
3 files changed, 18 insertions, 26 deletions
diff --git a/arch/x86/include/asm/lguest.h b/arch/x86/include/asm/lguest.h index e2d4a4afa8c3..3bbc07a57a31 100644 --- a/arch/x86/include/asm/lguest.h +++ b/arch/x86/include/asm/lguest.h @@ -20,13 +20,10 @@ extern unsigned long switcher_addr; /* Found in switcher.S */ extern unsigned long default_idt_entries[]; -/* Declarations for definitions in lguest_guest.S */ -extern char lguest_noirq_start[], lguest_noirq_end[]; +/* Declarations for definitions in arch/x86/lguest/head_32.S */ +extern char lguest_noirq_iret[]; extern const char lgstart_cli[], lgend_cli[]; -extern const char lgstart_sti[], lgend_sti[]; -extern const char lgstart_popf[], lgend_popf[]; extern const char lgstart_pushf[], lgend_pushf[]; -extern const char lgstart_iret[], lgend_iret[]; extern void lguest_iret(void); extern void lguest_init(void); diff --git a/arch/x86/lguest/boot.c b/arch/x86/lguest/boot.c index 717908b16037..8f9a133cc099 100644 --- a/arch/x86/lguest/boot.c +++ b/arch/x86/lguest/boot.c @@ -87,8 +87,7 @@ struct lguest_data lguest_data = { .hcall_status = { [0 ... LHCALL_RING_SIZE-1] = 0xFF }, - .noirq_start = (u32)lguest_noirq_start, - .noirq_end = (u32)lguest_noirq_end, + .noirq_iret = (u32)lguest_noirq_iret, .kernel_address = PAGE_OFFSET, .blocked_interrupts = { 1 }, /* Block timer interrupts */ .syscall_vec = SYSCALL_VECTOR, @@ -262,7 +261,7 @@ PV_CALLEE_SAVE_REGS_THUNK(lguest_save_fl); PV_CALLEE_SAVE_REGS_THUNK(lguest_irq_disable); /*:*/ -/* These are in i386_head.S */ +/* These are in head_32.S */ extern void lg_irq_enable(void); extern void lg_restore_fl(unsigned long flags); @@ -1368,7 +1367,7 @@ static void lguest_restart(char *reason) * fit comfortably. * * First we need assembly templates of each of the patchable Guest operations, - * and these are in i386_head.S. + * and these are in head_32.S. */ /*G:060 We construct a table from the assembler templates: */ diff --git a/arch/x86/lguest/head_32.S b/arch/x86/lguest/head_32.S index 6ddfe4fc23c3..d5ae63f5ec5d 100644 --- a/arch/x86/lguest/head_32.S +++ b/arch/x86/lguest/head_32.S @@ -84,7 +84,7 @@ ENTRY(lg_irq_enable) * set lguest_data.irq_pending to X86_EFLAGS_IF. If it's not zero, we * jump to send_interrupts, otherwise we're done. */ - testl $0, lguest_data+LGUEST_DATA_irq_pending + cmpl $0, lguest_data+LGUEST_DATA_irq_pending jnz send_interrupts /* * One cool thing about x86 is that you can do many things without using @@ -133,9 +133,8 @@ ENTRY(lg_restore_fl) ret /*:*/ -/* These demark the EIP range where host should never deliver interrupts. */ -.global lguest_noirq_start -.global lguest_noirq_end +/* These demark the EIP where host should never deliver interrupts. */ +.global lguest_noirq_iret /*M:004 * When the Host reflects a trap or injects an interrupt into the Guest, it @@ -168,29 +167,26 @@ ENTRY(lg_restore_fl) * So we have to copy eflags from the stack to lguest_data.irq_enabled before * we do the "iret". * - * There are two problems with this: firstly, we need to use a register to do - * the copy and secondly, the whole thing needs to be atomic. The first - * problem is easy to solve: push %eax on the stack so we can use it, and then - * restore it at the end just before the real "iret". + * There are two problems with this: firstly, we can't clobber any registers + * and secondly, the whole thing needs to be atomic. The first problem + * is solved by using "push memory"/"pop memory" instruction pair for copying. * * The second is harder: copying eflags to lguest_data.irq_enabled will turn * interrupts on before we're finished, so we could be interrupted before we - * return to userspace or wherever. Our solution to this is to surround the - * code with lguest_noirq_start: and lguest_noirq_end: labels. We tell the + * return to userspace or wherever. Our solution to this is to tell the * Host that it is *never* to interrupt us there, even if interrupts seem to be - * enabled. + * enabled. (It's not necessary to protect pop instruction, since + * data gets updated only after it completes, so we only need to protect + * one instruction, iret). */ ENTRY(lguest_iret) - pushl %eax - movl 12(%esp), %eax -lguest_noirq_start: + pushl 2*4(%esp) /* * Note the %ss: segment prefix here. Normal data accesses use the * "ds" segment, but that will have already been restored for whatever * we're returning to (such as userspace): we can't trust it. The %ss: * prefix makes sure we use the stack segment, which is still valid. */ - movl %eax,%ss:lguest_data+LGUEST_DATA_irq_enabled - popl %eax + popl %ss:lguest_data+LGUEST_DATA_irq_enabled +lguest_noirq_iret: iret -lguest_noirq_end: |