| Message ID | 20231123055733.1002890-3-harshpb@linux.ibm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Introduce SPAPR_IRQ_NR_IPIS and fix max-cpus | expand |
On 11/23/23 06:57, Harsh Prateek Bora wrote: > Initialize the machine specific max_cpus limit as per the maximum range > of CPU IPIs available. Keeping between 4096 to 8192 will throw IRQ not > free error due to XIVE/XICS limitation and keeping beyond 8192 will hit > assert in tcg_region_init or spapr_xive_claim_irq. > > Logs: > > Without patch fix: > > [root@host build]# qemu-system-ppc64 -accel tcg -smp 10,maxcpus=4097 > qemu-system-ppc64: IRQ 4096 is not free > [root@host build]# > > On LPAR: > [root@host build]# qemu-system-ppc64 -accel tcg -smp 10,maxcpus=8193 > ** > ERROR:../tcg/region.c:774:tcg_region_init: assertion failed: > (region_size >= 2 * page_size) > Bail out! ERROR:../tcg/region.c:774:tcg_region_init: assertion failed: > (region_size >= 2 * page_size) > Aborted (core dumped) > [root@host build]# > > On x86: > [root@host build]# qemu-system-ppc64 -accel tcg -smp 10,maxcpus=8193 > qemu-system-ppc64: ../hw/intc/spapr_xive.c:596: spapr_xive_claim_irq: > Assertion `lisn < xive->nr_irqs' failed. > Aborted (core dumped) > [root@host build]# > > With patch fix: > [root@host build]# qemu-system-ppc64 -accel tcg -smp 10,maxcpus=4097 > qemu-system-ppc64: Invalid SMP CPUs 4097. The max CPUs supported by > machine 'pseries-8.2' is 4096 > [root@host build]# > > Signed-off-by: Harsh Prateek Bora <harshpb@linux.ibm.com> Reviewed-by: Cédric Le Goater <clg@kaod.org> Thanks, C. > --- > hw/ppc/spapr.c | 9 +++------ > 1 file changed, 3 insertions(+), 6 deletions(-) > > diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c > index df09aa9d6a..222d926f46 100644 > --- a/hw/ppc/spapr.c > +++ b/hw/ppc/spapr.c > @@ -4647,13 +4647,10 @@ static void spapr_machine_class_init(ObjectClass *oc, void *data) > mc->block_default_type = IF_SCSI; > > /* > - * Setting max_cpus to INT32_MAX. Both KVM and TCG max_cpus values > - * should be limited by the host capability instead of hardcoded. > - * max_cpus for KVM guests will be checked in kvm_init(), and TCG > - * guests are welcome to have as many CPUs as the host are capable > - * of emulate. > + * While KVM determines max cpus in kvm_init() using kvm_max_vcpus(), > + * In TCG the limit is restricted by the range of CPU IPIs available. > */ > - mc->max_cpus = INT32_MAX; > + mc->max_cpus = SPAPR_IRQ_NR_IPIS; > > mc->no_parallel = 1; > mc->default_boot_order = "";
On 23/11/23 14:21, Cédric Le Goater wrote: > On 11/23/23 06:57, Harsh Prateek Bora wrote: >> Initialize the machine specific max_cpus limit as per the maximum range >> of CPU IPIs available. Keeping between 4096 to 8192 will throw IRQ not >> free error due to XIVE/XICS limitation and keeping beyond 8192 will hit >> assert in tcg_region_init or spapr_xive_claim_irq. >> >> Logs: >> >> Without patch fix: >> >> [root@host build]# qemu-system-ppc64 -accel tcg -smp 10,maxcpus=4097 >> qemu-system-ppc64: IRQ 4096 is not free >> [root@host build]# >> >> On LPAR: >> [root@host build]# qemu-system-ppc64 -accel tcg -smp 10,maxcpus=8193 >> ** >> ERROR:../tcg/region.c:774:tcg_region_init: assertion failed: >> (region_size >= 2 * page_size) >> Bail out! ERROR:../tcg/region.c:774:tcg_region_init: assertion failed: >> (region_size >= 2 * page_size) >> Aborted (core dumped) >> [root@host build]# >> >> On x86: >> [root@host build]# qemu-system-ppc64 -accel tcg -smp 10,maxcpus=8193 >> qemu-system-ppc64: ../hw/intc/spapr_xive.c:596: spapr_xive_claim_irq: >> Assertion `lisn < xive->nr_irqs' failed. >> Aborted (core dumped) >> [root@host build]# >> >> With patch fix: >> [root@host build]# qemu-system-ppc64 -accel tcg -smp 10,maxcpus=4097 >> qemu-system-ppc64: Invalid SMP CPUs 4097. The max CPUs supported by >> machine 'pseries-8.2' is 4096 >> [root@host build]# >> >> Signed-off-by: Harsh Prateek Bora <harshpb@linux.ibm.com> > > > Reviewed-by: Cédric Le Goater <clg@kaod.org> > > Thanks, > > C. > > > >> --- >> hw/ppc/spapr.c | 9 +++------ >> 1 file changed, 3 insertions(+), 6 deletions(-) >> >> diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c >> index df09aa9d6a..222d926f46 100644 >> --- a/hw/ppc/spapr.c >> +++ b/hw/ppc/spapr.c >> @@ -4647,13 +4647,10 @@ static void >> spapr_machine_class_init(ObjectClass *oc, void *data) >> mc->block_default_type = IF_SCSI; >> /* >> - * Setting max_cpus to INT32_MAX. Both KVM and TCG max_cpus values >> - * should be limited by the host capability instead of hardcoded. >> - * max_cpus for KVM guests will be checked in kvm_init(), and TCG >> - * guests are welcome to have as many CPUs as the host are capable >> - * of emulate. >> + * While KVM determines max cpus in kvm_init() using >> kvm_max_vcpus(), >> + * In TCG the limit is restricted by the range of CPU IPIs >> available. >> */ >> - mc->max_cpus = INT32_MAX; >> + mc->max_cpus = SPAPR_IRQ_NR_IPIS; >> mc->no_parallel = 1; >> mc->default_boot_order = ""; > > I've applied these patches and verified on the latest upstream qemu. > The code is working as expected. Tested-by: Kowshik > Jois<kowsjois@linux.ibm.com>
diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c index df09aa9d6a..222d926f46 100644 --- a/hw/ppc/spapr.c +++ b/hw/ppc/spapr.c @@ -4647,13 +4647,10 @@ static void spapr_machine_class_init(ObjectClass *oc, void *data) mc->block_default_type = IF_SCSI; /* - * Setting max_cpus to INT32_MAX. Both KVM and TCG max_cpus values - * should be limited by the host capability instead of hardcoded. - * max_cpus for KVM guests will be checked in kvm_init(), and TCG - * guests are welcome to have as many CPUs as the host are capable - * of emulate. + * While KVM determines max cpus in kvm_init() using kvm_max_vcpus(), + * In TCG the limit is restricted by the range of CPU IPIs available. */ - mc->max_cpus = INT32_MAX; + mc->max_cpus = SPAPR_IRQ_NR_IPIS; mc->no_parallel = 1; mc->default_boot_order = "";
Initialize the machine specific max_cpus limit as per the maximum range of CPU IPIs available. Keeping between 4096 to 8192 will throw IRQ not free error due to XIVE/XICS limitation and keeping beyond 8192 will hit assert in tcg_region_init or spapr_xive_claim_irq. Logs: Without patch fix: [root@host build]# qemu-system-ppc64 -accel tcg -smp 10,maxcpus=4097 qemu-system-ppc64: IRQ 4096 is not free [root@host build]# On LPAR: [root@host build]# qemu-system-ppc64 -accel tcg -smp 10,maxcpus=8193 ** ERROR:../tcg/region.c:774:tcg_region_init: assertion failed: (region_size >= 2 * page_size) Bail out! ERROR:../tcg/region.c:774:tcg_region_init: assertion failed: (region_size >= 2 * page_size) Aborted (core dumped) [root@host build]# On x86: [root@host build]# qemu-system-ppc64 -accel tcg -smp 10,maxcpus=8193 qemu-system-ppc64: ../hw/intc/spapr_xive.c:596: spapr_xive_claim_irq: Assertion `lisn < xive->nr_irqs' failed. Aborted (core dumped) [root@host build]# With patch fix: [root@host build]# qemu-system-ppc64 -accel tcg -smp 10,maxcpus=4097 qemu-system-ppc64: Invalid SMP CPUs 4097. The max CPUs supported by machine 'pseries-8.2' is 4096 [root@host build]# Signed-off-by: Harsh Prateek Bora <harshpb@linux.ibm.com> --- hw/ppc/spapr.c | 9 +++------ 1 file changed, 3 insertions(+), 6 deletions(-)