From be5d5350a937cd8513b258739f1099420129e96f Mon Sep 17 00:00:00 2001 From: Yinghai Lu Date: Fri, 5 Dec 2008 18:58:33 -0800 Subject: [PATCH] x86: MSI start irq numbering from nr_irqs_gsi Impact: sanitize MSI irq number ordering from top-down to bottom-up Increase new MSI IRQs starting from nr_irqs_gsi (which is somewhere below 256), instead of decreasing from NR_IRQS. (The latter method can result in confusingly high IRQ numbers - if NR_CPUS is set to a high value and NR_IRQS scales up to a high value.) Signed-off-by: Yinghai Lu Signed-off-by: Ingo Molnar --- arch/x86/include/asm/io_apic.h | 2 +- arch/x86/kernel/io_apic.c | 24 +++++++++++++++++------- arch/x86/kernel/setup.c | 2 +- 3 files changed, 19 insertions(+), 9 deletions(-) diff --git a/arch/x86/include/asm/io_apic.h b/arch/x86/include/asm/io_apic.h index 6afd9933a7dd..b35e94c2d6df 100644 --- a/arch/x86/include/asm/io_apic.h +++ b/arch/x86/include/asm/io_apic.h @@ -188,7 +188,7 @@ extern void restore_IO_APIC_setup(void); extern void reinit_intr_remapped_IO_APIC(int); #endif -extern int probe_nr_irqs(void); +extern void probe_nr_irqs_gsi(void); #else /* !CONFIG_X86_IO_APIC */ #define io_apic_assign_pci_irqs 0 diff --git a/arch/x86/kernel/io_apic.c b/arch/x86/kernel/io_apic.c index 9870461ae933..0dcde74abd1d 100644 --- a/arch/x86/kernel/io_apic.c +++ b/arch/x86/kernel/io_apic.c @@ -2973,7 +2973,7 @@ unsigned int create_irq_nr(unsigned int irq_want) irq = 0; spin_lock_irqsave(&vector_lock, flags); - for (new = irq_want; new > 0; new--) { + for (new = irq_want; new < NR_IRQS; new++) { if (platform_legacy_irq(new)) continue; @@ -3001,11 +3001,14 @@ unsigned int create_irq_nr(unsigned int irq_want) return irq; } +static int nr_irqs_gsi = NR_IRQS_LEGACY; int create_irq(void) { + unsigned int irq_want; int irq; - irq = create_irq_nr(nr_irqs - 1); + irq_want = nr_irqs_gsi; + irq = create_irq_nr(irq_want); if (irq == 0) irq = -1; @@ -3281,7 +3284,7 @@ int arch_setup_msi_irq(struct pci_dev *dev, struct msi_desc *msidesc) int ret; unsigned int irq_want; - irq_want = nr_irqs - 1; + irq_want = nr_irqs_gsi; irq = create_irq_nr(irq_want); if (irq == 0) return -1; @@ -3321,11 +3324,11 @@ int arch_setup_msi_irqs(struct pci_dev *dev, int nvec, int type) int index = 0; #endif - irq_want = nr_irqs - 1; + irq_want = nr_irqs_gsi; sub_handle = 0; list_for_each_entry(msidesc, &dev->msi_list, list) { irq = create_irq_nr(irq_want); - irq_want--; + irq_want++; if (irq == 0) return -1; #ifdef CONFIG_INTR_REMAP @@ -3674,9 +3677,16 @@ int __init io_apic_get_redir_entries (int ioapic) return reg_01.bits.entries; } -int __init probe_nr_irqs(void) +void __init probe_nr_irqs_gsi(void) { - return NR_IRQS; + int idx; + int nr = 0; + + for (idx = 0; idx < nr_ioapics; idx++) + nr += io_apic_get_redir_entries(idx) + 1; + + if (nr > nr_irqs_gsi) + nr_irqs_gsi = nr; } /* -------------------------------------------------------------------------- diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c index 9d5674f7b6cc..a3834f123206 100644 --- a/arch/x86/kernel/setup.c +++ b/arch/x86/kernel/setup.c @@ -1082,7 +1082,7 @@ void __init setup_arch(char **cmdline_p) ioapic_init_mappings(); /* need to wait for io_apic is mapped */ - nr_irqs = probe_nr_irqs(); + probe_nr_irqs_gsi(); kvm_guest_init(); -- GitLab