Re: Nested paging in nested SVM setup

From: Valentine Sinitsyn <valentine.sinitsyn@gmail.com>
To: Paolo Bonzini <pbonzini@redhat.com>,
	Jan Kiszka <jan.kiszka@siemens.com>,
	kvm@vger.kernel.org
Subject: Re: Nested paging in nested SVM setup
Date: Wed, 20 Aug 2014 13:37:26 +0600	[thread overview]
Message-ID: <53F45036.1070309@gmail.com> (raw)
In-Reply-To: <53F44645.2000708@redhat.com>

Hi Paolo,

On 20.08.2014 12:55, Paolo Bonzini wrote:
> Is the 0x23c always the same?
No, it's just a garbage - I've seen other values as well (0x80 last time).

>  Can you try this patch?
Sure. It does print a warning:

[ 2176.722098] ------------[ cut here ]------------
[ 2176.722118] WARNING: CPU: 0 PID: 1488 at 
/home/val/kvm-kmod/x86/x86.c:368 kvm_multiple_exception+0x121/0x130 [kvm]()
[ 2176.722121] Modules linked in: kvm_amd(O) kvm(O) amd_freq_sensitivity 
snd_hda_codec_realtek snd_hda_codec_hdmi snd_hda_codec_generic 
crct10dif_pclmul crc32_pclmul crc32c_intel ghash_clmulni_intel 
snd_hda_intel aesni_intel snd_hda_controller radeon snd_hda_codec 
ipmi_si aes_x86_64 ipmi_msghandler snd_hwdep ttm r8169 ppdev mii lrw 
gf128mul snd_pcm glue_helper drm_kms_helper snd_timer fam15h_power evdev 
drm shpchp snd ablk_helper cryptd microcode mac_hid soundcore serio_raw 
pcspkr i2c_algo_bit k10temp i2c_piix4 i2c_core parport_pc parport hwmon 
edac_core tpm_tis edac_mce_amd tpm video button acpi_cpufreq processor 
ext4 crc16 mbcache jbd2 sd_mod crc_t10dif crct10dif_common atkbd libps2 
ahci libahci ohci_pci ohci_hcd ehci_pci xhci_hcd libata ehci_hcd usbcore 
scsi_mod usb_common i8042 serio [last unloaded: kvm]

[ 2176.722217] CPU: 0 PID: 1488 Comm: qemu-system-x86 Tainted: G 
W  O  3.16.1-1-ARCH #1
[ 2176.722221] Hardware name: To Be Filled By O.E.M. To Be Filled By 
O.E.M./IMB-A180, BIOS L0.17 05/24/2013
[ 2176.722224]  0000000000000000 0000000025350f51 ffff8800919fbbc0 
ffffffff8152ae6c
[ 2176.722229]  0000000000000000 ffff8800919fbbf8 ffffffff8106e45d 
ffff880037f68000
[ 2176.722234]  0000000000000080 0000000000000001 00000000000081a4 
0000000000000000
[ 2176.722239] Call Trace:
[ 2176.722250]  [<ffffffff8152ae6c>] dump_stack+0x4d/0x6f
[ 2176.722257]  [<ffffffff8106e45d>] warn_slowpath_common+0x7d/0xa0
[ 2176.722262]  [<ffffffff8106e58a>] warn_slowpath_null+0x1a/0x20
[ 2176.722275]  [<ffffffffa0651e41>] kvm_multiple_exception+0x121/0x130 
[kvm]
[ 2176.722288]  [<ffffffffa06594f8>] x86_emulate_instruction+0x548/0x640 
[kvm]
[ 2176.722303]  [<ffffffffa06653e1>] kvm_mmu_page_fault+0x91/0xf0 [kvm]
[ 2176.722310]  [<ffffffffa04eb6a7>] pf_interception+0xd7/0x180 [kvm_amd]
[ 2176.722317]  [<ffffffff8104e876>] ? native_apic_mem_write+0x6/0x10
[ 2176.722323]  [<ffffffffa04ef261>] handle_exit+0x141/0x9d0 [kvm_amd]
[ 2176.722335]  [<ffffffffa065512c>] ? kvm_set_cr8+0x1c/0x20 [kvm]
[ 2176.722341]  [<ffffffffa04ea3e0>] ? nested_svm_get_tdp_cr3+0x20/0x20 
[kvm_amd]
[ 2176.722355]  [<ffffffffa065adc7>] 
kvm_arch_vcpu_ioctl_run+0x597/0x1210 [kvm]
[ 2176.722368]  [<ffffffffa065705b>] ? kvm_arch_vcpu_load+0xbb/0x200 [kvm]
[ 2176.722378]  [<ffffffffa064a152>] kvm_vcpu_ioctl+0x2b2/0x5c0 [kvm]
[ 2176.722384]  [<ffffffff810b66b4>] ? __wake_up+0x44/0x50
[ 2176.722390]  [<ffffffff81200dcc>] ? fsnotify+0x28c/0x370
[ 2176.722397]  [<ffffffff811d4a70>] do_vfs_ioctl+0x2d0/0x4b0
[ 2176.722403]  [<ffffffff811df18e>] ? __fget+0x6e/0xb0
[ 2176.722408]  [<ffffffff811d4cd1>] SyS_ioctl+0x81/0xa0
[ 2176.722414]  [<ffffffff81530be9>] system_call_fastpath+0x16/0x1b
[ 2176.722418] ---[ end trace b0f81744c5a5ea4a ]---

Thanks,
Valentine