| Message ID | 20211209220840.14889-1-dwmw2@infradead.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v2,1/4] target/i386: Fix sanity check on max APIC ID / X2APIC enablement | expand |
On Thu, Dec 09, 2021 at 10:08:37PM +0000, David Woodhouse wrote: > The check on x86ms->apic_id_limit in pc_machine_done() had two problems. > > Firstly, we need KVM to support the X2APIC API in order to allow IRQ > delivery to APICs >= 255. So we need to call/check kvm_enable_x2apic(), > which was done elsewhere in *some* cases but not all. > > Secondly, microvm needs the same check. So move it from pc_machine_done() > to x86_cpus_init() where it will work for both. > > The check in kvm_cpu_instance_init() is now redundant and can be dropped. > > Signed-off-by: David Woodhouse <dwmw2@infradead.org> > Acked-by: Claudio Fontana <cfontana@suse.de> > --- > hw/i386/pc.c | 8 -------- > hw/i386/x86.c | 16 ++++++++++++++++ > target/i386/kvm/kvm-cpu.c | 2 +- > 3 files changed, 17 insertions(+), 9 deletions(-) > > diff --git a/hw/i386/pc.c b/hw/i386/pc.c > index a2ef40ecbc..9959f93216 100644 > --- a/hw/i386/pc.c > +++ b/hw/i386/pc.c > @@ -736,14 +736,6 @@ void pc_machine_done(Notifier *notifier, void *data) > /* update FW_CFG_NB_CPUS to account for -device added CPUs */ > fw_cfg_modify_i16(x86ms->fw_cfg, FW_CFG_NB_CPUS, x86ms->boot_cpus); > } > - > - > - if (x86ms->apic_id_limit > 255 && !xen_enabled() && > - !kvm_irqchip_in_kernel()) { > - error_report("current -smp configuration requires kernel " > - "irqchip support."); > - exit(EXIT_FAILURE); > - } > } > > void pc_guest_info_init(PCMachineState *pcms) > diff --git a/hw/i386/x86.c b/hw/i386/x86.c > index b84840a1bb..f64639b873 100644 > --- a/hw/i386/x86.c > +++ b/hw/i386/x86.c > @@ -39,6 +39,7 @@ > #include "sysemu/replay.h" > #include "sysemu/sysemu.h" > #include "sysemu/cpu-timers.h" > +#include "sysemu/xen.h" > #include "trace.h" > > #include "hw/i386/x86.h" > @@ -136,6 +137,21 @@ void x86_cpus_init(X86MachineState *x86ms, int default_cpu_version) > */ > x86ms->apic_id_limit = x86_cpu_apic_id_from_index(x86ms, > ms->smp.max_cpus - 1) + 1; > + > + /* > + * Can we support APIC ID 255 or higher? > + * > + * Under Xen: yes. > + * With userspace emulated lapic: no > + * With KVM's in-kernel lapic: only if X2APIC API is enabled. > + */ > + if (x86ms->apic_id_limit > 255 && !xen_enabled() && > + (!kvm_irqchip_in_kernel() || !kvm_enable_x2apic())) { I'm wondering whether we should still leave it be in the accel code, or is therer something that guarantees when reaching here kvm accel is initialized? > + error_report("current -smp configuration requires kernel " > + "irqchip and X2APIC API support."); > + exit(EXIT_FAILURE); > + } > + > possible_cpus = mc->possible_cpu_arch_ids(ms); > for (i = 0; i < ms->smp.cpus; i++) { > x86_cpu_new(x86ms, possible_cpus->cpus[i].arch_id, &error_fatal); > diff --git a/target/i386/kvm/kvm-cpu.c b/target/i386/kvm/kvm-cpu.c > index d95028018e..c60cb2dafb 100644 > --- a/target/i386/kvm/kvm-cpu.c > +++ b/target/i386/kvm/kvm-cpu.c > @@ -165,7 +165,7 @@ static void kvm_cpu_instance_init(CPUState *cs) > /* only applies to builtin_x86_defs cpus */ > if (!kvm_irqchip_in_kernel()) { > x86_cpu_change_kvm_default("x2apic", "off"); > - } else if (kvm_irqchip_is_split() && kvm_enable_x2apic()) { > + } else if (kvm_irqchip_is_split()) { > x86_cpu_change_kvm_default("kvm-msi-ext-dest-id", "on"); > } > > -- > 2.31.1 >
On Thu, Dec 09, 2021 at 10:08:37PM +0000, David Woodhouse wrote: > The check on x86ms->apic_id_limit in pc_machine_done() had two problems. > > Firstly, we need KVM to support the X2APIC API in order to allow IRQ > delivery to APICs >= 255. So we need to call/check kvm_enable_x2apic(), > which was done elsewhere in *some* cases but not all. > > Secondly, microvm needs the same check. So move it from pc_machine_done() > to x86_cpus_init() where it will work for both. > > The check in kvm_cpu_instance_init() is now redundant and can be dropped. > > Signed-off-by: David Woodhouse <dwmw2@infradead.org> > Acked-by: Claudio Fontana <cfontana@suse.de> Could I get an ack from KVM maintainers on this one please? Thanks! > --- > hw/i386/pc.c | 8 -------- > hw/i386/x86.c | 16 ++++++++++++++++ > target/i386/kvm/kvm-cpu.c | 2 +- > 3 files changed, 17 insertions(+), 9 deletions(-) > > diff --git a/hw/i386/pc.c b/hw/i386/pc.c > index a2ef40ecbc..9959f93216 100644 > --- a/hw/i386/pc.c > +++ b/hw/i386/pc.c > @@ -736,14 +736,6 @@ void pc_machine_done(Notifier *notifier, void *data) > /* update FW_CFG_NB_CPUS to account for -device added CPUs */ > fw_cfg_modify_i16(x86ms->fw_cfg, FW_CFG_NB_CPUS, x86ms->boot_cpus); > } > - > - > - if (x86ms->apic_id_limit > 255 && !xen_enabled() && > - !kvm_irqchip_in_kernel()) { > - error_report("current -smp configuration requires kernel " > - "irqchip support."); > - exit(EXIT_FAILURE); > - } > } > > void pc_guest_info_init(PCMachineState *pcms) > diff --git a/hw/i386/x86.c b/hw/i386/x86.c > index b84840a1bb..f64639b873 100644 > --- a/hw/i386/x86.c > +++ b/hw/i386/x86.c > @@ -39,6 +39,7 @@ > #include "sysemu/replay.h" > #include "sysemu/sysemu.h" > #include "sysemu/cpu-timers.h" > +#include "sysemu/xen.h" > #include "trace.h" > > #include "hw/i386/x86.h" > @@ -136,6 +137,21 @@ void x86_cpus_init(X86MachineState *x86ms, int default_cpu_version) > */ > x86ms->apic_id_limit = x86_cpu_apic_id_from_index(x86ms, > ms->smp.max_cpus - 1) + 1; > + > + /* > + * Can we support APIC ID 255 or higher? > + * > + * Under Xen: yes. > + * With userspace emulated lapic: no > + * With KVM's in-kernel lapic: only if X2APIC API is enabled. > + */ > + if (x86ms->apic_id_limit > 255 && !xen_enabled() && > + (!kvm_irqchip_in_kernel() || !kvm_enable_x2apic())) { > + error_report("current -smp configuration requires kernel " > + "irqchip and X2APIC API support."); > + exit(EXIT_FAILURE); > + } > + > possible_cpus = mc->possible_cpu_arch_ids(ms); > for (i = 0; i < ms->smp.cpus; i++) { > x86_cpu_new(x86ms, possible_cpus->cpus[i].arch_id, &error_fatal); > diff --git a/target/i386/kvm/kvm-cpu.c b/target/i386/kvm/kvm-cpu.c > index d95028018e..c60cb2dafb 100644 > --- a/target/i386/kvm/kvm-cpu.c > +++ b/target/i386/kvm/kvm-cpu.c > @@ -165,7 +165,7 @@ static void kvm_cpu_instance_init(CPUState *cs) > /* only applies to builtin_x86_defs cpus */ > if (!kvm_irqchip_in_kernel()) { > x86_cpu_change_kvm_default("x2apic", "off"); > - } else if (kvm_irqchip_is_split() && kvm_enable_x2apic()) { > + } else if (kvm_irqchip_is_split()) { > x86_cpu_change_kvm_default("kvm-msi-ext-dest-id", "on"); > } > > -- > 2.31.1
diff --git a/hw/i386/pc.c b/hw/i386/pc.c index a2ef40ecbc..9959f93216 100644 --- a/hw/i386/pc.c +++ b/hw/i386/pc.c @@ -736,14 +736,6 @@ void pc_machine_done(Notifier *notifier, void *data) /* update FW_CFG_NB_CPUS to account for -device added CPUs */ fw_cfg_modify_i16(x86ms->fw_cfg, FW_CFG_NB_CPUS, x86ms->boot_cpus); } - - - if (x86ms->apic_id_limit > 255 && !xen_enabled() && - !kvm_irqchip_in_kernel()) { - error_report("current -smp configuration requires kernel " - "irqchip support."); - exit(EXIT_FAILURE); - } } void pc_guest_info_init(PCMachineState *pcms) diff --git a/hw/i386/x86.c b/hw/i386/x86.c index b84840a1bb..f64639b873 100644 --- a/hw/i386/x86.c +++ b/hw/i386/x86.c @@ -39,6 +39,7 @@ #include "sysemu/replay.h" #include "sysemu/sysemu.h" #include "sysemu/cpu-timers.h" +#include "sysemu/xen.h" #include "trace.h" #include "hw/i386/x86.h" @@ -136,6 +137,21 @@ void x86_cpus_init(X86MachineState *x86ms, int default_cpu_version) */ x86ms->apic_id_limit = x86_cpu_apic_id_from_index(x86ms, ms->smp.max_cpus - 1) + 1; + + /* + * Can we support APIC ID 255 or higher? + * + * Under Xen: yes. + * With userspace emulated lapic: no + * With KVM's in-kernel lapic: only if X2APIC API is enabled. + */ + if (x86ms->apic_id_limit > 255 && !xen_enabled() && + (!kvm_irqchip_in_kernel() || !kvm_enable_x2apic())) { + error_report("current -smp configuration requires kernel " + "irqchip and X2APIC API support."); + exit(EXIT_FAILURE); + } + possible_cpus = mc->possible_cpu_arch_ids(ms); for (i = 0; i < ms->smp.cpus; i++) { x86_cpu_new(x86ms, possible_cpus->cpus[i].arch_id, &error_fatal); diff --git a/target/i386/kvm/kvm-cpu.c b/target/i386/kvm/kvm-cpu.c index d95028018e..c60cb2dafb 100644 --- a/target/i386/kvm/kvm-cpu.c +++ b/target/i386/kvm/kvm-cpu.c @@ -165,7 +165,7 @@ static void kvm_cpu_instance_init(CPUState *cs) /* only applies to builtin_x86_defs cpus */ if (!kvm_irqchip_in_kernel()) { x86_cpu_change_kvm_default("x2apic", "off"); - } else if (kvm_irqchip_is_split() && kvm_enable_x2apic()) { + } else if (kvm_irqchip_is_split()) { x86_cpu_change_kvm_default("kvm-msi-ext-dest-id", "on"); }