qemu/target/i386
Eduardo Habkost af95cafb87 i386: Omit all-zeroes entries from KVM CPUID table
KVM has a 80-entry limit at KVM_SET_CPUID2.  With the
introduction of CPUID[0x1F], it is now possible to hit this limit
with unusual CPU configurations, e.g.:

  $ ./x86_64-softmmu/qemu-system-x86_64 \
    -smp 1,dies=2,maxcpus=2 \
    -cpu EPYC,check=off,enforce=off \
    -machine accel=kvm
  qemu-system-x86_64: kvm_init_vcpu failed: Argument list too long

This happens because QEMU adds a lot of all-zeroes CPUID entries
for unused CPUID leaves.  In the example above, we end up
creating 48 all-zeroes CPUID entries.

KVM already returns all-zeroes when emulating the CPUID
instruction if an entry is missing, so the all-zeroes entries are
redundant.  Skip those entries.  This reduces the CPUID table
size by half while keeping CPUID output unchanged.

Reported-by: Yumei Huang <yuhuang@redhat.com>
Fixes: https://bugzilla.redhat.com/show_bug.cgi?id=1741508
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Message-Id: <20190822225210.32541-1-ehabkost@redhat.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
2019-10-15 18:34:44 -03:00
..
hvf target/i386: drop the duplicated definition of cpuid AVX512_VBMI macro 2019-10-15 18:34:44 -03:00
arch_dump.c dump: add kernel_gs_base to QEMU CPU state 2018-07-16 16:13:34 +02:00
arch_memory_mapping.c exec,dump,i386,ppc,s390x: don't include exec/cpu-all.h explicitly 2017-09-19 18:21:33 +02:00
bpt_helper.c target/i386: Use env_cpu, env_archcpu 2019-06-10 07:03:42 -07:00
cc_helper_template.h
cc_helper.c target-i386: Use ctpop helper 2017-01-10 08:49:59 -08:00
cpu-param.h tcg: Split out target/arch/cpu-param.h 2019-06-10 07:03:34 -07:00
cpu-qom.h hw/core: Move cpu.c, cpu.h from qom/ to hw/core/ 2019-08-21 13:24:01 +02:00
cpu.c i386: Fix legacy guest with xsave panic on host kvm without update cpuid. 2019-10-15 18:34:44 -03:00
cpu.h target/i386: drop the duplicated definition of cpuid AVX512_VBMI macro 2019-10-15 18:34:44 -03:00
excp_helper.c sysemu: Split sysemu/runstate.h off sysemu/sysemu.h 2019-08-16 13:37:36 +02:00
fpu_helper.c target/i386: Use env_cpu, env_archcpu 2019-06-10 07:03:42 -07:00
gdbstub.c Include qemu-common.h exactly where needed 2019-06-12 13:20:20 +02:00
hax-all.c sysemu: Split sysemu/runstate.h off sysemu/sysemu.h 2019-08-16 13:37:36 +02:00
hax-i386.h Clean up ill-advised or unusual header guards 2019-05-13 08:58:55 +02:00
hax-interface.h Clean up ill-advised or unusual header guards 2019-05-13 08:58:55 +02:00
hax-mem.c qemu/queue.h: leave head structs anonymous unless necessary 2019-01-11 15:46:55 +01:00
hax-posix.c hax: Support for Linux hosts 2019-01-11 13:57:24 +01:00
hax-posix.h Clean up header guards that don't match their file name 2019-05-13 08:58:55 +02:00
hax-windows.c target: Do not include "exec/exec-all.h" if it is not necessary 2018-06-01 14:15:10 +02:00
hax-windows.h hax: Support guest RAM sizes of 4GB or more 2018-02-13 11:44:13 +01:00
helper.c Fix wrong behavior of cpu_memory_rw_debug() function in SMM 2019-10-04 18:49:18 +02:00
helper.h target/i386: Implement CPUID_EXT_RDRAND 2019-05-22 12:38:54 -04:00
hyperv-proto.h i386/kvm: add support for Direct Mode for Hyper-V synthetic timers 2019-06-21 02:29:39 +02:00
hyperv-stub.c target/i386: fix feature check in hyperv-stub.c 2019-07-05 22:16:46 +02:00
hyperv.c i386/kvm: convert hyperv enlightenments properties from bools to bits 2019-06-21 02:29:38 +02:00
hyperv.h hyperv: qom-ify SynIC 2018-10-19 13:44:14 +02:00
int_helper.c target/i386: Implement CPUID_EXT_RDRAND 2019-05-22 12:38:54 -04:00
kvm_i386.h target/i386: kvm: Demand nested migration kernel capabilities only when vCPU may have enabled VMX 2019-07-19 18:01:47 +02:00
kvm-stub.c Include qemu-common.h exactly where needed 2019-06-12 13:20:20 +02:00
kvm.c i386: Omit all-zeroes entries from KVM CPUID table 2019-10-15 18:34:44 -03:00
machine.c kvm: i386: halt poll control MSR support 2019-08-20 17:26:17 +02:00
Makefile.objs target-i386: add kvm stubs to user-mode emulators 2019-03-11 16:33:49 +01:00
mem_helper.c cpu: Replace ENV_GET_CPU with env_cpu 2019-06-10 07:03:34 -07:00
misc_helper.c target/i386: Use env_cpu, env_archcpu 2019-06-10 07:03:42 -07:00
monitor.c Include generated QAPI headers less 2019-08-16 13:31:51 +02:00
mpx_helper.c target/i386: move cpu_sync_bndcs_hflags() function 2017-07-05 09:12:44 +02:00
ops_sse_header.h target-i386: Use ctpop helper 2017-01-10 08:49:59 -08:00
ops_sse.h target/i386: Return 'indefinite integer value' for invalid SSE fp->int conversions 2019-08-20 17:26:20 +02:00
seg_helper.c target/i386: Use env_cpu, env_archcpu 2019-06-10 07:03:42 -07:00
sev_i386.h Include generated QAPI headers less 2019-08-16 13:31:51 +02:00
sev-stub.c Include qemu-common.h exactly where needed 2019-06-12 13:20:20 +02:00
sev.c sysemu: Split sysemu/runstate.h off sysemu/sysemu.h 2019-08-16 13:37:36 +02:00
shift_helper_template.h
smm_helper.c target/i386: Use env_cpu, env_archcpu 2019-06-10 07:03:42 -07:00
svm_helper.c target/i386: Use env_cpu, env_archcpu 2019-06-10 07:03:42 -07:00
svm.h target-i386: Add NPT support 2018-07-02 15:41:18 +02:00
TODO
trace-events trace-events: Shorten file names in comments 2019-03-22 16:18:07 +00:00
translate.c tcg: TCGMemOp is now accelerator independent MemOp 2019-09-03 08:30:38 -07:00
whp-dispatch.h Normalize position of header guard 2019-06-12 13:20:20 +02:00
whpx-all.c target/i386: Fix broken build with WHPX enabled 2019-09-26 19:00:53 +01:00
xsave_helper.c Include qemu-common.h exactly where needed 2019-06-12 13:20:20 +02:00