Re: [PATCH v7 2/4] KVM: async_pf: Add L1 guest async_pf #PF vmexit handler

From: "Radim Krčmář" <rkrcmar@redhat.com>
To: Wanpeng Li <kernellwp@gmail.com>
Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
	Paolo Bonzini <pbonzini@redhat.com>,
	Wanpeng Li <wanpeng.li@hotmail.com>
Subject: Re: [PATCH v7 2/4] KVM: async_pf: Add L1 guest async_pf #PF vmexit handler
Date: Wed, 12 Jul 2017 23:44:09 +0200	[thread overview]
Message-ID: <20170712214408.GH3326@potion> (raw)
In-Reply-To: <1498705321-3927-3-git-send-email-wanpeng.li@hotmail.com>

2017-06-28 20:01-0700, Wanpeng Li:
> From: Wanpeng Li <wanpeng.li@hotmail.com>
> 
> This patch adds the L1 guest async page fault #PF vmexit handler, such
> #PF is converted into vmexit from L2 to L1 on #PF which is then handled
> by L1 similar to ordinary async page fault.
> 
> Cc: Paolo Bonzini <pbonzini@redhat.com>
> Cc: Radim Krčmář <rkrcmar@redhat.com>
> Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
> ---

This patch breaks SVM, so I've taken the series off kvm/queue for now;
I'll look into it tomorrow.  The error is:

 BUG: unable to handle kernel paging request at ffffffffc0735ad2
 IP: report_bug+0x94/0x120
 PGD 43e14067 
 P4D 43e14067 
 PUD 43e16067 
 PMD 2164bf067 
 PTE 80000002181fc161

 Oops: 0003 [#1] SMP
 Modules linked in: kvm_amd(OE) kvm(OE) irqbypass(E) xt_CHECKSUM iptable_mangle ipt_MASQUERADE nf_nat_masquerade_ipv4 iptable_nat nf_nat_ipv4 nf_nat nf_conntrack_ipv4 nf_defrag_ipv4 xt_conntrack nf_conntrack libcrc32c tun bridge stp llc ebtable_filter ebtables ip6table_filter ip6_tables sunrpc snd_hda_codec_realtek snd_hda_codec_generic snd_hda_codec_hdmi snd_hda_intel snd_hda_codec snd_hwdep snd_hda_core snd_seq snd_seq_device snd_pcm ppdev joydev parport_serial parport_pc snd_timer parport k10temp sky2 snd shpchp sp5100_tco acpi_cpufreq wmi soundcore i2c_piix4 amdkfd amd_iommu_v2 radeon i2c_algo_bit drm_kms_helper uas serio_raw usb_storage ttm pata_atiixp drm ata_generic pata_acpi pata_jmicron [last unloaded: irqbypass]
 CPU: 3 PID: 1868 Comm: CPU 0/KVM Tainted: G           OE   4.12.0+ #1
 Hardware name: To Be Filled By O.E.M. To Be Filled By O.E.M./To be filled by O.E.M., BIOS 080014  03/07/2008
 task: ffff8bcbe3f1b140 task.stack: ffffabb481970000
 RIP: 0010:report_bug+0x94/0x120
 RSP: 0018:ffffabb481973a70 EFLAGS: 00010202
 RAX: 0000000000000907 RBX: ffffabb481973bd8 RCX: ffffffffc0735ac8
 RDX: 0000000000000001 RSI: 0000000000000ed0 RDI: 0000000000000001
 RBP: ffffabb481973a90 R08: 0000000000000001 R09: 7f9f279200000000
 R10: ffffabb4819739d0 R11: 0000000000000000 R12: ffffffffc07023d0
 R13: ffffffffc0733078 R14: 0000000000000004 R15: ffffabb481973bd8
 FS:  0000000000000000(0000) GS:ffff8bcbe7400000(0000) knlGS:0000000000000000
 CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
 CR2: ffffffffc0735ad2 CR3: 00000002189d7000 CR4: 00000000000006e0
 Call Trace:
  ? kvm_handle_page_fault+0x1f0/0x200 [kvm]
  fixup_bug+0x2e/0x50
  do_trap+0x119/0x150
  do_error_trap+0xa3/0x160
  ? kvm_handle_page_fault+0x1f0/0x200 [kvm]
  ? trace_hardirqs_off_thunk+0x1a/0x1c
  do_invalid_op+0x20/0x30
  invalid_op+0x1e/0x30
 RIP: 0010:kvm_handle_page_fault+0x1f0/0x200 [kvm]
 RSP: 0018:ffffabb481973c80 EFLAGS: 00010202
 RAX: 0000000000000000 RBX: ffff8bcbd7550000 RCX: 0000000000000000
 RDX: 00000000fffffff0 RSI: 0000000000000014 RDI: ffff8bcbd7550000
 RBP: ffffabb481973ca0 R08: 0000000000000001 R09: 27624b3d00000000
 R10: ffffabb481973ca8 R11: ffff8bcbe3fb25f0 R12: 00000000fffffff0
 R13: 0000000000000014 R14: ffff8bcbd7550000 R15: ffff8bcbd7550000
  pf_interception+0x20/0x30 [kvm_amd]
  handle_exit+0x213/0xbb0 [kvm_amd]
  kvm_arch_vcpu_ioctl_run+0x7f1/0x1ae0 [kvm]
  kvm_vcpu_ioctl+0x2ac/0x6f0 [kvm]
  ? kvm_vcpu_ioctl+0x2ac/0x6f0 [kvm]
  ? sched_clock+0x9/0x10
  ? debug_lockdep_rcu_enabled+0x1d/0x30
  do_vfs_ioctl+0xa6/0x6c0
  SyS_ioctl+0x79/0x90
  entry_SYSCALL_64_fastpath+0x1f/0xbe
 RIP: 0033:0x7fabf6d815c7
 RSP: 002b:00007fabe87e77c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
 RAX: ffffffffffffffda RBX: 0000000000010000 RCX: 00007fabf6d815c7
 RDX: 0000000000000000 RSI: 000000000000ae80 RDI: 0000000000000010
 RBP: 000055a7cb502fe0 R08: 000055a7cb51e410 R09: 000055a7cb509390
 R10: 000055a7cdb01000 R11: 0000000000000246 R12: 000055a7cdace0a6
 R13: 0000000000000000 R14: 00007fac00621000 R15: 000055a7cdace000
 Code: 74 59 0f b7 41 0a 4c 63 69 04 0f b7 71 08 89 c7 49 01 cd 83 e7 01 a8 02 74 15 66 85 ff 74 10 a8 04 ba 01 00 00 00 75 26 83 c8 04 <66> 89 41 0a 66 85 ff 74 49 0f b6 49 0b 4c 89 e2 45 31 c9 49 89 
 RIP: report_bug+0x94/0x120 RSP: ffffabb481973a70
 CR2: ffffffffc0735ad2
 ---[ end trace aec3a1f15664a4af ]---
 BUG: sleeping function called from invalid context at ./include/linux/percpu-rwsem.h:33
 in_atomic(): 0, irqs_disabled(): 1, pid: 1868, name: CPU 0/KVM
 INFO: lockdep is turned off.
 irq event stamp: 1868
 hardirqs last  enabled at (1867): [<ffffffffa398eaab>] restore_regs_and_iret+0x0/0x1d
 hardirqs last disabled at (1868): [<ffffffffa398f7dc>] error_entry+0x7c/0xd0
 softirqs last  enabled at (1834): [<ffffffffa3992f62>] __do_softirq+0x382/0x4ed
 softirqs last disabled at (1817): [<ffffffffa30b9a2f>] irq_exit+0x10f/0x120
 CPU: 3 PID: 1868 Comm: CPU 0/KVM Tainted: G      D    OE   4.12.0+ #1
 Hardware name: To Be Filled By O.E.M. To Be Filled By O.E.M./To be filled by O.E.M., BIOS 080014  03/07/2008
 Call Trace:
  dump_stack+0x8e/0xcd
  ___might_sleep+0x164/0x250
  __might_sleep+0x4a/0x80
  exit_signals+0x33/0x240
  do_exit+0xb4/0xd20
  ? SyS_ioctl+0x79/0x90
  rewind_stack_do_exit+0x17/0x20
 RIP: 0033:0x7fabf6d815c7
 RSP: 002b:00007fabe87e77c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
 RAX: ffffffffffffffda RBX: 0000000000010000 RCX: 00007fabf6d815c7
 RDX: 0000000000000000 RSI: 000000000000ae80 RDI: 0000000000000010
 RBP: 000055a7cb502fe0 R08: 000055a7cb51e410 R09: 000055a7cb509390
 R10: 000055a7cdb01000 R11: 0000000000000246 R12: 000055a7cdace0a6
 R13: 0000000000000000 R14: 00007fac00621000 R15: 000055a7cdace000