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linux_dsm_epyc7002/arch
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Andrea Arcangeli 3dcb2a3fa5 KVM: retpolines: x86: eliminate retpoline from svm.c exit handlers 
It's enough to check the exit value and issue a direct call to avoid
the retpoline for all the common vmexit reasons.

After this commit is applied, here the most common retpolines executed
under a high resolution timer workload in the guest on a SVM host:

[..]
@[
    trace_retpoline+1
    __trace_retpoline+30
    __x86_indirect_thunk_rax+33
    ktime_get_update_offsets_now+70
    hrtimer_interrupt+131
    smp_apic_timer_interrupt+106
    apic_timer_interrupt+15
    start_sw_timer+359
    restart_apic_timer+85
    kvm_set_msr_common+1497
    msr_interception+142
    vcpu_enter_guest+684
    kvm_arch_vcpu_ioctl_run+261
    kvm_vcpu_ioctl+559
    do_vfs_ioctl+164
    ksys_ioctl+96
    __x64_sys_ioctl+22
    do_syscall_64+89
    entry_SYSCALL_64_after_hwframe+68
]: 1940
@[
    trace_retpoline+1
    __trace_retpoline+30
    __x86_indirect_thunk_r12+33
    force_qs_rnp+217
    rcu_gp_kthread+1270
    kthread+268
    ret_from_fork+34
]: 4644
@[]: 25095
@[
    trace_retpoline+1
    __trace_retpoline+30
    __x86_indirect_thunk_rax+33
    lapic_next_event+28
    clockevents_program_event+148
    hrtimer_start_range_ns+528
    start_sw_timer+356
    restart_apic_timer+85
    kvm_set_msr_common+1497
    msr_interception+142
    vcpu_enter_guest+684
    kvm_arch_vcpu_ioctl_run+261
    kvm_vcpu_ioctl+559
    do_vfs_ioctl+164
    ksys_ioctl+96
    __x64_sys_ioctl+22
    do_syscall_64+89
    entry_SYSCALL_64_after_hwframe+68
]: 41474
@[
    trace_retpoline+1
    __trace_retpoline+30
    __x86_indirect_thunk_rax+33
    clockevents_program_event+148
    hrtimer_start_range_ns+528
    start_sw_timer+356
    restart_apic_timer+85
    kvm_set_msr_common+1497
    msr_interception+142
    vcpu_enter_guest+684
    kvm_arch_vcpu_ioctl_run+261
    kvm_vcpu_ioctl+559
    do_vfs_ioctl+164
    ksys_ioctl+96
    __x64_sys_ioctl+22
    do_syscall_64+89
    entry_SYSCALL_64_after_hwframe+68
]: 41474
@[
    trace_retpoline+1
    __trace_retpoline+30
    __x86_indirect_thunk_rax+33
    ktime_get+58
    clockevents_program_event+84
    hrtimer_start_range_ns+528
    start_sw_timer+356
    restart_apic_timer+85
    kvm_set_msr_common+1497
    msr_interception+142
    vcpu_enter_guest+684
    kvm_arch_vcpu_ioctl_run+261
    kvm_vcpu_ioctl+559
    do_vfs_ioctl+164
    ksys_ioctl+96
    __x64_sys_ioctl+22
    do_syscall_64+89
    entry_SYSCALL_64_after_hwframe+68
]: 41887
@[
    trace_retpoline+1
    __trace_retpoline+30
    __x86_indirect_thunk_rax+33
    lapic_next_event+28
    clockevents_program_event+148
    hrtimer_try_to_cancel+168
    hrtimer_cancel+21
    kvm_set_lapic_tscdeadline_msr+43
    kvm_set_msr_common+1497
    msr_interception+142
    vcpu_enter_guest+684
    kvm_arch_vcpu_ioctl_run+261
    kvm_vcpu_ioctl+559
    do_vfs_ioctl+164
    ksys_ioctl+96
    __x64_sys_ioctl+22
    do_syscall_64+89
    entry_SYSCALL_64_after_hwframe+68
]: 42723
@[
    trace_retpoline+1
    __trace_retpoline+30
    __x86_indirect_thunk_rax+33
    clockevents_program_event+148
    hrtimer_try_to_cancel+168
    hrtimer_cancel+21
    kvm_set_lapic_tscdeadline_msr+43
    kvm_set_msr_common+1497
    msr_interception+142
    vcpu_enter_guest+684
    kvm_arch_vcpu_ioctl_run+261
    kvm_vcpu_ioctl+559
    do_vfs_ioctl+164
    ksys_ioctl+96
    __x64_sys_ioctl+22
    do_syscall_64+89
    entry_SYSCALL_64_after_hwframe+68
]: 42766
@[
    trace_retpoline+1
    __trace_retpoline+30
    __x86_indirect_thunk_rax+33
    ktime_get+58
    clockevents_program_event+84
    hrtimer_try_to_cancel+168
    hrtimer_cancel+21
    kvm_set_lapic_tscdeadline_msr+43
    kvm_set_msr_common+1497
    msr_interception+142
    vcpu_enter_guest+684
    kvm_arch_vcpu_ioctl_run+261
    kvm_vcpu_ioctl+559
    do_vfs_ioctl+164
    ksys_ioctl+96
    __x64_sys_ioctl+22
    do_syscall_64+89
    entry_SYSCALL_64_after_hwframe+68
]: 42848
@[
    trace_retpoline+1
    __trace_retpoline+30
    __x86_indirect_thunk_rax+33
    ktime_get+58
    start_sw_timer+279
    restart_apic_timer+85
    kvm_set_msr_common+1497
    msr_interception+142
    vcpu_enter_guest+684
    kvm_arch_vcpu_ioctl_run+261
    kvm_vcpu_ioctl+559
    do_vfs_ioctl+164
    ksys_ioctl+96
    __x64_sys_ioctl+22
    do_syscall_64+89
    entry_SYSCALL_64_after_hwframe+68
]: 499845

@total: 1780243

SVM has no TSC based programmable preemption timer so it is invoking
ktime_get() frequently.

Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2019-11-15 11:43:57 +01:00
..
alpha mm: introduce MADV_PAGEOUT 2019-09-25 17:51:41 -07:00
arc mm: treewide: clarify pgtable_page_{ctor,dtor}() naming 2019-09-26 10:10:44 -07:00
arm Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2019-10-19 17:09:11 -04:00
arm64 KVM/arm fixes for 5.4, take #2 2019-10-22 13:31:29 +02:00
c6x mm: consolidate pgtable_cache_init() and pgd_cache_init() 2019-09-24 15:54:09 -07:00
csky csky-for-linus-5.4-rc1: arch/csky patches for 5.4-rc1 2019-09-30 10:16:17 -07:00
h8300 mm: consolidate pgtable_cache_init() and pgd_cache_init() 2019-09-24 15:54:09 -07:00
hexagon mm: treewide: clarify pgtable_page_{ctor,dtor}() naming 2019-09-26 10:10:44 -07:00
ia64 Merge branch 'akpm' (patches from Andrew) 2019-09-24 16:10:23 -07:00
m68k mm: treewide: clarify pgtable_page_{ctor,dtor}() naming 2019-09-26 10:10:44 -07:00
microblaze Merge branch 'akpm' (patches from Andrew) 2019-09-24 16:10:23 -07:00
mips USB fixes for 5.4-rc3 2019-10-12 15:37:12 -07:00
nds32 mm: consolidate pgtable_cache_init() and pgd_cache_init() 2019-09-24 15:54:09 -07:00
nios2 nios2 update for v5.4-rc1 2019-09-27 13:02:19 -07:00
openrisc mm: treewide: clarify pgtable_page_{ctor,dtor}() naming 2019-09-26 10:10:44 -07:00
parisc parisc: Fix vmap memory leak in ioremap()/iounmap() 2019-10-14 21:44:17 +02:00
powerpc KVM PPC update for 5.5 2019-11-01 00:35:55 +01:00
riscv RISC-V: fix virtual address overlapped in FIXADDR_START and VMEMMAP_START 2019-10-15 22:47:41 -07:00
s390 s390/uaccess: avoid (false positive) compiler warnings 2019-10-11 12:27:25 +02:00
sh mm: treewide: clarify pgtable_page_{ctor,dtor}() naming 2019-09-26 10:10:44 -07:00
sparc sparc64: disable fast-GUP due to unexplained oopses 2019-10-15 09:56:36 -07:00
um mm: treewide: clarify pgtable_page_{ctor,dtor}() naming 2019-09-26 10:10:44 -07:00
unicore32 mm: treewide: clarify pgtable_page_{ctor,dtor}() naming 2019-09-26 10:10:44 -07:00
x86 KVM: retpolines: x86: eliminate retpoline from svm.c exit handlers 2019-11-15 11:43:57 +01:00
xtensa xtensa: fix change_bit in exclusive access option 2019-10-16 00:14:33 -07:00
.gitignore
Kconfig arm64, mm: make randomization selected by generic topdown mmap layout 2019-09-24 15:54:11 -07:00