From 8965c1c0950d459d99b8b81dfc1ab02e3d2cfb08 Mon Sep 17 00:00:00 2001 From: Jeremy Fitzhardinge Date: Tue, 16 Oct 2007 11:51:29 -0700 Subject: paravirt: clean up lazy mode handling Currently, the set_lazy_mode pv_op is overloaded with 5 functions: 1. enter lazy cpu mode 2. leave lazy cpu mode 3. enter lazy mmu mode 4. leave lazy mmu mode 5. flush pending batched operations This complicates each paravirt backend, since it needs to deal with all the possible state transitions, handling flushing, etc. In particular, flushing is quite distinct from the other 4 functions, and seems to just cause complication. This patch removes the set_lazy_mode operation, and adds "enter" and "leave" lazy mode operations on mmu_ops and cpu_ops. All the logic associated with enter and leaving lazy states is now in common code (basically BUG_ONs to make sure that no mode is current when entering a lazy mode, and make sure that the mode is current when leaving). Also, flush is handled in a common way, by simply leaving and re-entering the lazy mode. The result is that the Xen, lguest and VMI lazy mode implementations are much simpler. Signed-off-by: Jeremy Fitzhardinge Cc: Andi Kleen Cc: Zach Amsden Cc: Rusty Russell Cc: Avi Kivity Cc: Anthony Liguory Cc: "Glauber de Oliveira Costa" Cc: Jun Nakajima --- drivers/lguest/lguest.c | 32 +++++++++++--------------------- 1 file changed, 11 insertions(+), 21 deletions(-) (limited to 'drivers/lguest') diff --git a/drivers/lguest/lguest.c b/drivers/lguest/lguest.c index ca9b844..c302629 100644 --- a/drivers/lguest/lguest.c +++ b/drivers/lguest/lguest.c @@ -97,29 +97,17 @@ static cycle_t clock_base; * them as a batch when lazy_mode is eventually turned off. Because hypercalls * are reasonably expensive, batching them up makes sense. For example, a * large mmap might update dozens of page table entries: that code calls - * lguest_lazy_mode(PARAVIRT_LAZY_MMU), does the dozen updates, then calls - * lguest_lazy_mode(PARAVIRT_LAZY_NONE). + * paravirt_enter_lazy_mmu(), does the dozen updates, then calls + * lguest_leave_lazy_mode(). * * So, when we're in lazy mode, we call async_hypercall() to store the call for * future processing. When lazy mode is turned off we issue a hypercall to * flush the stored calls. - * - * There's also a hack where "mode" is set to "PARAVIRT_LAZY_FLUSH" which - * indicates we're to flush any outstanding calls immediately. This is used - * when an interrupt handler does a kmap_atomic(): the page table changes must - * happen immediately even if we're in the middle of a batch. Usually we're - * not, though, so there's nothing to do. */ -static enum paravirt_lazy_mode lazy_mode; /* Note: not SMP-safe! */ -static void lguest_lazy_mode(enum paravirt_lazy_mode mode) + */ +static void lguest_leave_lazy_mode(void) { - if (mode == PARAVIRT_LAZY_FLUSH) { - if (unlikely(lazy_mode != PARAVIRT_LAZY_NONE)) - hcall(LHCALL_FLUSH_ASYNC, 0, 0, 0); - } else { - lazy_mode = mode; - if (mode == PARAVIRT_LAZY_NONE) - hcall(LHCALL_FLUSH_ASYNC, 0, 0, 0); - } + paravirt_leave_lazy(paravirt_get_lazy_mode()); + hcall(LHCALL_FLUSH_ASYNC, 0, 0, 0); } static void lazy_hcall(unsigned long call, @@ -127,7 +115,7 @@ static void lazy_hcall(unsigned long call, unsigned long arg2, unsigned long arg3) { - if (lazy_mode == PARAVIRT_LAZY_NONE) + if (paravirt_get_lazy_mode() == PARAVIRT_LAZY_NONE) hcall(call, arg1, arg2, arg3); else async_hcall(call, arg1, arg2, arg3); @@ -1011,6 +999,8 @@ __init void lguest_init(void *boot) pv_cpu_ops.write_gdt_entry = lguest_write_gdt_entry; pv_cpu_ops.write_idt_entry = lguest_write_idt_entry; pv_cpu_ops.wbinvd = lguest_wbinvd; + pv_cpu_ops.lazy_mode.enter = paravirt_enter_lazy_cpu; + pv_cpu_ops.lazy_mode.leave = lguest_leave_lazy_mode; /* pagetable management */ pv_mmu_ops.write_cr3 = lguest_write_cr3; @@ -1022,6 +1012,8 @@ __init void lguest_init(void *boot) pv_mmu_ops.set_pmd = lguest_set_pmd; pv_mmu_ops.read_cr2 = lguest_read_cr2; pv_mmu_ops.read_cr3 = lguest_read_cr3; + pv_mmu_ops.lazy_mode.enter = paravirt_enter_lazy_mmu; + pv_mmu_ops.lazy_mode.leave = lguest_leave_lazy_mode; #ifdef CONFIG_X86_LOCAL_APIC /* apic read/write intercepts */ @@ -1034,8 +1026,6 @@ __init void lguest_init(void *boot) pv_time_ops.get_wallclock = lguest_get_wallclock; pv_time_ops.time_init = lguest_time_init; - pv_misc_ops.set_lazy_mode = lguest_lazy_mode; - /* Now is a good time to look at the implementations of these functions * before returning to the rest of lguest_init(). */ -- cgit v1.1