From bb6f1d9a99f1947d91693de62ed54ac3bf1e2dfe Mon Sep 17 00:00:00 2001 From: Rusty Russell Date: Thu, 16 Dec 2010 17:03:13 -0600 Subject: lguest: fix crash lguest_time_init fe25c7fc2e "x86: lguest: Convert to new irq chip functions" converted enable_lguest_irq() to take a struct irq_data *, but didn't fix the one internal caller. Signed-off-by: Rusty Russell To: x86@kernel.org --- arch/x86/lguest/boot.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'arch/x86/lguest/boot.c') diff --git a/arch/x86/lguest/boot.c b/arch/x86/lguest/boot.c index 73b1e1a1f489..45e64b37b237 100644 --- a/arch/x86/lguest/boot.c +++ b/arch/x86/lguest/boot.c @@ -1002,7 +1002,7 @@ static void lguest_time_init(void) clockevents_register_device(&lguest_clockevent); /* Finally, we unblock the timer interrupt. */ - enable_lguest_irq(0); + clear_bit(0, lguest_data.blocked_interrupts); } /* -- cgit v1.2.3 From bb4093deb259ea9c92415796a6a139e35272f8a8 Mon Sep 17 00:00:00 2001 From: Rusty Russell Date: Thu, 16 Dec 2010 17:03:15 -0600 Subject: lguest: restore boot speed lguest is dumb and drops *all* the pagetables for set_pte (which is only used for kernel mapping manipulation, so it's OK without highmem). But it's used a lot in boot, too. As a guest optimization, we suppressed this flushing until the first page switch. Now we have initial_page_table, that happens much earlier, so extend the heuristic to wait until we switch to something other than the swapper_pg_dir or initial_page_table. As measured on my laptop under kvm, this dropped the time-to-mount-root from 48 seconds to 4.3 seconds. Signed-off-by: Rusty Russell --- arch/x86/lguest/boot.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) (limited to 'arch/x86/lguest/boot.c') diff --git a/arch/x86/lguest/boot.c b/arch/x86/lguest/boot.c index 45e64b37b237..24e49737df7a 100644 --- a/arch/x86/lguest/boot.c +++ b/arch/x86/lguest/boot.c @@ -531,7 +531,10 @@ static void lguest_write_cr3(unsigned long cr3) { lguest_data.pgdir = cr3; lazy_hcall1(LHCALL_NEW_PGTABLE, cr3); - cr3_changed = true; + + /* These two page tables are simple, linear, and used during boot */ + if (cr3 != __pa(swapper_pg_dir) && cr3 != __pa(initial_page_table)) + cr3_changed = true; } static unsigned long lguest_read_cr3(void) @@ -703,9 +706,9 @@ static void lguest_set_pmd(pmd_t *pmdp, pmd_t pmdval) * to forget all of them. Fortunately, this is very rare. * * ... except in early boot when the kernel sets up the initial pagetables, - * which makes booting astonishingly slow: 1.83 seconds! So we don't even tell - * the Host anything changed until we've done the first page table switch, - * which brings boot back to 0.25 seconds. + * which makes booting astonishingly slow: 48 seconds! So we don't even tell + * the Host anything changed until we've done the first real page table switch, + * which brings boot back to 4.3 seconds. */ static void lguest_set_pte(pte_t *ptep, pte_t pteval) { -- cgit v1.2.3 From da32dac101263fb5b155407507c548e3ac2a6a2a Mon Sep 17 00:00:00 2001 From: Rusty Russell Date: Thu, 16 Dec 2010 17:03:15 -0600 Subject: lguest: populate initial_page_table 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 Cc: Jeremy Fitzhardinge Cc: Konrad Rzeszutek Wilk To: x86@kernel.org --- arch/x86/lguest/boot.c | 3 --- 1 file changed, 3 deletions(-) (limited to 'arch/x86/lguest/boot.c') diff --git a/arch/x86/lguest/boot.c b/arch/x86/lguest/boot.c index 24e49737df7a..4996cf5f73a0 100644 --- a/arch/x86/lguest/boot.c +++ b/arch/x86/lguest/boot.c @@ -1352,9 +1352,6 @@ __init void lguest_init(void) */ switch_to_new_gdt(0); - /* We actually boot with all memory mapped, but let's say 128MB. */ - max_pfn_mapped = (128*1024*1024) >> PAGE_SHIFT; - /* * The Host<->Guest Switcher lives at the top of our address space, and * the Host told us how big it is when we made LGUEST_INIT hypercall: -- cgit v1.2.3