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From: Sean Christopherson <sean.j.christopherson@intel.com>
To: Ben Gardon <bgardon@google.com>
Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
	Cannon Matthews <cannonmatthews@google.com>,
	Paolo Bonzini <pbonzini@redhat.com>, Peter Xu <peterx@redhat.com>,
	Peter Shier <pshier@google.com>,
	Peter Feiner <pfeiner@google.com>,
	Junaid Shahid <junaids@google.com>,
	Jim Mattson <jmattson@google.com>,
	Yulei Zhang <yulei.kernel@gmail.com>,
	Wanpeng Li <kernellwp@gmail.com>,
	Vitaly Kuznetsov <vkuznets@redhat.com>,
	Xiao Guangrong <xiaoguangrong.eric@gmail.com>
Subject: Re: [PATCH 03/22] kvm: mmu: Init / Uninit the TDP MMU
Date: Wed, 30 Sep 2020 09:57:34 -0700	[thread overview]
Message-ID: <20200930165734.GE32672@linux.intel.com> (raw)
In-Reply-To: <20200925212302.3979661-4-bgardon@google.com>

On Fri, Sep 25, 2020 at 02:22:43PM -0700, Ben Gardon wrote:
> diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c
> new file mode 100644
> index 0000000000000..8241e18c111e6
> --- /dev/null
> +++ b/arch/x86/kvm/mmu/tdp_mmu.c
> @@ -0,0 +1,34 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +
> +#include "tdp_mmu.h"
> +
> +static bool __read_mostly tdp_mmu_enabled = true;
> +module_param_named(tdp_mmu, tdp_mmu_enabled, bool, 0644);

This param should not exist until the TDP MMU is fully functional, e.g. running
KVM against "kvm: mmu: Support zapping SPTEs in the TDP MMU" immediately hits a
BUG() in the rmap code.  I haven't wrapped my head around the entire series to
grok whether it make sense to incrementally enable the TDP MMU, but my gut says
that's probably non-sensical.  The local variable can exist (default to false)
so that you can flip a single switch to enable the code instead of having to
plumb in the variable to its consumers.

  kernel BUG at arch/x86/kvm/mmu/mmu.c:1427!
  invalid opcode: 0000 [#1] SMP
  CPU: 4 PID: 1218 Comm: stable Not tainted 5.9.0-rc4+ #44
  Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015
  RIP: 0010:rmap_get_first.isra.0+0x51/0x60 [kvm]
  Code: <0f> 0b 45 31 c0 4c 89 c0 c3 66 0f 1f 44 00 00 0f 1f 44 00 00 49 b9
  RSP: 0018:ffffc9000099fb50 EFLAGS: 00010246
  RAX: 0000000000000000 RBX: 0000000000001000 RCX: 0000000000000000
  RDX: ffffc9000099fb60 RSI: ffffc9000099fb58 RDI: ffff88816b1a7ec8
  RBP: ffff88816b1a7e70 R08: ffff888173c95000 R09: ffff88816b1a7448
  R10: 00000000000000f8 R11: ffff88817bd29c70 R12: ffffc90000981000
  R13: ffffc9000099fbac R14: ffffc90000989a88 R15: ffff88816b1a7ec8
  FS:  00007f7a755fd700(0000) GS:ffff88817bd00000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  CR2: 00007f7a60141000 CR3: 000000016b031004 CR4: 0000000000172ea0
  Call Trace:
   __kvm_mmu_prepare_zap_page+0x98/0x330 [kvm]
   kvm_mmu_zap_all_fast+0x100/0x190 [kvm]
   kvm_page_track_flush_slot+0x54/0x80 [kvm]
   kvm_set_memslot+0x198/0x640 [kvm]
   kvm_delete_memslot+0x59/0xc0 [kvm]
   __kvm_set_memory_region+0x494/0x560 [kvm]
   ? khugepaged+0x470/0x2230
   ? mem_cgroup_charge_statistics.isra.0+0x1c/0x40
   kvm_set_memory_region+0x27/0x40 [kvm]
   kvm_vm_ioctl+0x379/0xca0 [kvm]
   ? do_user_addr_fault+0x1ad/0x3a7
   __x64_sys_ioctl+0x83/0xb0
   do_syscall_64+0x33/0x80
   entry_SYSCALL_64_after_hwframe+0x44/0xa9

  parent reply	other threads:[~2020-09-30 16:57 UTC|newest]

Thread overview: 105+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-25 21:22 [PATCH 00/22] Introduce the TDP MMU Ben Gardon
2020-09-25 21:22 ` [PATCH 01/22] kvm: mmu: Separate making SPTEs from set_spte Ben Gardon
2020-09-30  4:55   ` Sean Christopherson
2020-09-30 23:03     ` Ben Gardon
2020-09-25 21:22 ` [PATCH 02/22] kvm: mmu: Introduce tdp_iter Ben Gardon
2020-09-26  0:04   ` Paolo Bonzini
2020-09-30  5:06     ` Sean Christopherson
2020-09-26  0:54   ` Paolo Bonzini
2020-09-30  5:08   ` Sean Christopherson
2020-09-30  5:24   ` Sean Christopherson
2020-09-30  6:24     ` Paolo Bonzini
2020-09-30 23:20   ` Eric van Tassell
2020-09-30 23:34     ` Paolo Bonzini
2020-10-01  0:07       ` Sean Christopherson
2020-09-25 21:22 ` [PATCH 03/22] kvm: mmu: Init / Uninit the TDP MMU Ben Gardon
2020-09-26  0:06   ` Paolo Bonzini
2020-09-30  5:34   ` Sean Christopherson
2020-09-30 18:36     ` Ben Gardon
2020-09-30 16:57   ` Sean Christopherson [this message]
2020-09-30 17:39     ` Paolo Bonzini
2020-09-30 18:42       ` Ben Gardon
2020-09-25 21:22 ` [PATCH 04/22] kvm: mmu: Allocate and free TDP MMU roots Ben Gardon
2020-09-30  6:06   ` Sean Christopherson
2020-09-30  6:26     ` Paolo Bonzini
2020-09-30 15:38       ` Sean Christopherson
2020-10-12 22:59     ` Ben Gardon
2020-10-12 23:59       ` Sean Christopherson
2020-09-25 21:22 ` [PATCH 05/22] kvm: mmu: Add functions to handle changed TDP SPTEs Ben Gardon
2020-09-26  0:39   ` Paolo Bonzini
2020-09-28 17:23     ` Paolo Bonzini
2020-09-25 21:22 ` [PATCH 06/22] kvm: mmu: Make address space ID a property of memslots Ben Gardon
2020-09-30  6:10   ` Sean Christopherson
2020-09-30 23:11     ` Ben Gardon
2020-09-25 21:22 ` [PATCH 07/22] kvm: mmu: Support zapping SPTEs in the TDP MMU Ben Gardon
2020-09-26  0:14   ` Paolo Bonzini
2020-09-30  6:15   ` Sean Christopherson
2020-09-30  6:28     ` Paolo Bonzini
2020-09-25 21:22 ` [PATCH 08/22] kvm: mmu: Separate making non-leaf sptes from link_shadow_page Ben Gardon
2020-09-25 21:22 ` [PATCH 09/22] kvm: mmu: Remove disallowed_hugepage_adjust shadow_walk_iterator arg Ben Gardon
2020-09-30 16:19   ` Sean Christopherson
2020-09-25 21:22 ` [PATCH 10/22] kvm: mmu: Add TDP MMU PF handler Ben Gardon
2020-09-26  0:24   ` Paolo Bonzini
2020-09-30 16:37   ` Sean Christopherson
2020-09-30 16:55     ` Paolo Bonzini
2020-09-30 17:37     ` Paolo Bonzini
2020-10-06 22:35       ` Ben Gardon
2020-10-06 22:33     ` Ben Gardon
2020-10-07 20:55       ` Sean Christopherson
2020-09-25 21:22 ` [PATCH 11/22] kvm: mmu: Factor out allocating a new tdp_mmu_page Ben Gardon
2020-09-26  0:22   ` Paolo Bonzini
2020-09-30 18:53     ` Ben Gardon
2020-09-25 21:22 ` [PATCH 12/22] kvm: mmu: Allocate struct kvm_mmu_pages for all pages in TDP MMU Ben Gardon
2020-09-25 21:22 ` [PATCH 13/22] kvm: mmu: Support invalidate range MMU notifier for " Ben Gardon
2020-09-30 17:03   ` Sean Christopherson
2020-09-30 23:15     ` Ben Gardon
2020-09-30 23:24       ` Sean Christopherson
2020-09-30 23:27         ` Ben Gardon
2020-09-25 21:22 ` [PATCH 14/22] kvm: mmu: Add access tracking for tdp_mmu Ben Gardon
2020-09-26  0:32   ` Paolo Bonzini
2020-09-30 17:48   ` Sean Christopherson
2020-10-06 23:38     ` Ben Gardon
2020-09-25 21:22 ` [PATCH 15/22] kvm: mmu: Support changed pte notifier in tdp MMU Ben Gardon
2020-09-26  0:33   ` Paolo Bonzini
2020-09-28 15:11   ` Paolo Bonzini
2020-10-07 16:53     ` Ben Gardon
2020-10-07 17:18       ` Paolo Bonzini
2020-10-07 17:30         ` Ben Gardon
2020-10-07 17:54           ` Paolo Bonzini
2020-09-25 21:22 ` [PATCH 16/22] kvm: mmu: Add dirty logging handler for changed sptes Ben Gardon
2020-09-26  0:45   ` Paolo Bonzini
2020-09-25 21:22 ` [PATCH 17/22] kvm: mmu: Support dirty logging for the TDP MMU Ben Gardon
2020-09-26  1:04   ` Paolo Bonzini
2020-10-08 18:27     ` Ben Gardon
2020-09-29 15:07   ` Paolo Bonzini
2020-09-30 18:04   ` Sean Christopherson
2020-09-30 18:08     ` Paolo Bonzini
2020-09-25 21:22 ` [PATCH 18/22] kvm: mmu: Support disabling dirty logging for the tdp MMU Ben Gardon
2020-09-26  1:09   ` Paolo Bonzini
2020-10-07 16:30     ` Ben Gardon
2020-10-07 17:21       ` Paolo Bonzini
2020-10-07 17:28         ` Ben Gardon
2020-10-07 17:53           ` Paolo Bonzini
2020-09-25 21:22 ` [PATCH 19/22] kvm: mmu: Support write protection for nesting in " Ben Gardon
2020-09-30 18:06   ` Sean Christopherson
2020-09-25 21:23 ` [PATCH 20/22] kvm: mmu: NX largepage recovery for TDP MMU Ben Gardon
2020-09-26  1:14   ` Paolo Bonzini
2020-09-30 22:23     ` Ben Gardon
2020-09-29 18:24   ` Paolo Bonzini
2020-09-30 18:15   ` Sean Christopherson
2020-09-30 19:56     ` Paolo Bonzini
2020-09-30 22:33       ` Ben Gardon
2020-09-30 22:27     ` Ben Gardon
2020-09-25 21:23 ` [PATCH 21/22] kvm: mmu: Support MMIO in the " Ben Gardon
2020-09-30 18:19   ` Sean Christopherson
2020-09-25 21:23 ` [PATCH 22/22] kvm: mmu: Don't clear write flooding count for direct roots Ben Gardon
2020-09-26  1:25   ` Paolo Bonzini
2020-10-05 22:48     ` Ben Gardon
2020-10-05 23:44       ` Sean Christopherson
2020-10-06 16:19         ` Ben Gardon
2020-09-26  1:14 ` [PATCH 00/22] Introduce the TDP MMU Paolo Bonzini
2020-09-28 17:31 ` Paolo Bonzini
2020-09-29 17:40   ` Ben Gardon
2020-09-29 18:10     ` Paolo Bonzini
2020-09-30  6:19 ` Sean Christopherson
2020-09-30  6:30   ` Paolo Bonzini

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