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From: Joerg Roedel <jroedel@suse.de>
To: Andy Lutomirski <luto@kernel.org>
Cc: Joerg Roedel <joro@8bytes.org>, X86 ML <x86@kernel.org>,
	"H. Peter Anvin" <hpa@zytor.com>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Thomas Hellstrom <thellstrom@vmware.com>,
	Jiri Slaby <jslaby@suse.cz>,
	Dan Williams <dan.j.williams@intel.com>,
	Tom Lendacky <thomas.lendacky@amd.com>,
	Juergen Gross <jgross@suse.com>,
	Kees Cook <keescook@chromium.org>,
	LKML <linux-kernel@vger.kernel.org>,
	kvm list <kvm@vger.kernel.org>,
	Linux Virtualization <virtualization@lists.linux-foundation.org>
Subject: Re: [PATCH 70/70] x86/sev-es: Add NMI state tracking
Date: Thu, 19 Mar 2020 20:26:54 +0100	[thread overview]
Message-ID: <20200319192654.GD611@suse.de> (raw)
In-Reply-To: <CALCETrXY5M87C1Fc3QvTkc6MdbQ_3gAuOPUeWJktAzK4T60QNQ@mail.gmail.com>

On Thu, Mar 19, 2020 at 11:40:39AM -0700, Andy Lutomirski wrote:
 
> Nope.  A nested NMI will reset the interrupted NMI's return frame to
> cause it to run again when it's done.  I don't think this will have
> any real interaction with #VC.  There's no longjmp() here.

Ahh, so I misunderstood that part, in this case your proposal of sending
the NMI-complete message right at the beginning of do_nmi() should work
just fine. I will test this and see how it works out.

> I certainly *like* preventing nesting, but I don't think we really
> want a whole alternate NMI path just for a couple of messed-up AMD
> generations.  And the TF trick is not so pretty either.

Indeed, if it could be avoided, it should.

> 
> > > This causes us to pop the NMI frame off the stack.  Assuming the NMI
> > > restart logic is invoked (which is maybe impossible?), we get #DB,
> > > which presumably is actually delivered.  And we end up on the #DB
> > > stack, which might already have been in use, so we have a potential
> > > increase in nesting.  Also, #DB may be called from an unexpected
> > > context.
> >
> > An SEV-ES hypervisor is required to intercept #DB, which means that the
> > #DB exception actually ends up being a #VC exception. So it will not end
> > up on the #DB stack.
> 
> With your patch set, #DB doesn't seem to end up on the #DB stack either.

Right, it does not use the #DB stack or shift-ist stuff. Maybe it
should, is this needed for anything else than making entry code
debugable by kgdb?

Regards,

	Joerg

  reply	other threads:[~2020-03-19 19:27 UTC|newest]

Thread overview: 181+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-19  9:12 [RFC PATCH 00/70 v2] x86: SEV-ES Guest Support Joerg Roedel
2020-03-19  9:12 ` [PATCH 01/70] KVM: SVM: Add GHCB definitions Joerg Roedel
2020-03-23 13:23   ` [PATCH] KVM: SVM: Use __packed shorthard Borislav Petkov
2020-03-24 12:43     ` Joerg Roedel
2020-03-19  9:12 ` [PATCH 02/70] KVM: SVM: Add GHCB Accessor functions Joerg Roedel
2020-03-19  9:13 ` [PATCH 03/70] x86/cpufeatures: Add SEV-ES CPU feature Joerg Roedel
2020-03-19  9:13 ` [PATCH 04/70] x86/traps: Move some definitions to <asm/trap_defs.h> Joerg Roedel
2020-03-19  9:13 ` [PATCH 05/70] x86/insn: Make inat-tables.c suitable for pre-decompression code Joerg Roedel
2020-03-25 15:39   ` Borislav Petkov
2020-03-27  3:02     ` Masami Hiramatsu
2020-04-16 15:24       ` Joerg Roedel
2020-04-17 12:50         ` Masami Hiramatsu
2020-04-17 13:39           ` Joerg Roedel
2020-03-19  9:13 ` [PATCH 06/70] x86/umip: Factor out instruction fetch Joerg Roedel
2020-03-26 17:21   ` Borislav Petkov
2020-03-19  9:13 ` [PATCH 07/70] x86/umip: Factor out instruction decoding Joerg Roedel
2020-03-26 17:24   ` Borislav Petkov
2020-03-19  9:13 ` [PATCH 08/70] x86/insn: Add insn_get_modrm_reg_off() Joerg Roedel
2020-03-27  3:57   ` Masami Hiramatsu
2020-03-19  9:13 ` [PATCH 09/70] x86/insn: Add insn_rep_prefix() helper Joerg Roedel
2020-03-27  3:56   ` Masami Hiramatsu
2020-03-19  9:13 ` [PATCH 10/70] x86/boot/compressed: Fix debug_puthex() parameter type Joerg Roedel
2020-03-28 11:23   ` [tip: x86/boot] " tip-bot2 for Joerg Roedel
2020-03-19  9:13 ` [PATCH 11/70] x86/boot/compressed/64: Disable red-zone usage Joerg Roedel
2020-03-31 13:16   ` Borislav Petkov
2020-03-19  9:13 ` [PATCH 12/70] x86/boot/compressed/64: Add IDT Infrastructure Joerg Roedel
2020-04-07  2:21   ` Arvind Sankar
2020-04-16 13:30     ` Joerg Roedel
2020-03-19  9:13 ` [PATCH 13/70] x86/boot/compressed/64: Rename kaslr_64.c to ident_map_64.c Joerg Roedel
2020-03-19  9:13 ` [PATCH 14/70] x86/boot/compressed/64: Add page-fault handler Joerg Roedel
2020-04-02 11:49   ` Borislav Petkov
2020-03-19  9:13 ` [PATCH 15/70] x86/boot/compressed/64: Always switch to own page-table Joerg Roedel
2020-04-06 11:56   ` Borislav Petkov
2020-03-19  9:13 ` [PATCH 16/70] x86/boot/compressed/64: Don't pre-map memory in KASLR code Joerg Roedel
2020-03-19  9:13 ` [PATCH 17/70] x86/boot/compressed/64: Change add_identity_map() to take start and end Joerg Roedel
2020-03-19  9:13 ` [PATCH 18/70] x86/boot/compressed/64: Add stage1 #VC handler Joerg Roedel
2020-03-20 21:16   ` David Rientjes
2020-03-20 22:19     ` Joerg Roedel
2020-04-06 12:41   ` Borislav Petkov
2020-03-19  9:13 ` [PATCH 19/70] x86/boot/compressed/64: Call set_sev_encryption_mask earlier Joerg Roedel
2020-03-19  9:13 ` [PATCH 20/70] x86/boot/compressed/64: Check return value of kernel_ident_mapping_init() Joerg Roedel
2020-03-19  9:13 ` [PATCH 21/70] x86/boot/compressed/64: Add function to map a page unencrypted Joerg Roedel
2020-03-20 20:53   ` David Rientjes
2020-03-20 21:02     ` Dave Hansen
2020-03-20 22:12       ` Joerg Roedel
2020-03-20 22:26         ` Dave Hansen
2020-03-21 15:40           ` Joerg Roedel
2020-03-19  9:13 ` [PATCH 22/70] x86/boot/compressed/64: Setup GHCB Based VC Exception handler Joerg Roedel
2020-03-19  9:13 ` [PATCH 23/70] x86/sev-es: Add support for handling IOIO exceptions Joerg Roedel
2020-03-20 21:03   ` David Rientjes
2020-03-20 22:24     ` Joerg Roedel
2020-03-19  9:13 ` [PATCH 24/70] x86/fpu: Move xgetbv()/xsetbv() into separate header Joerg Roedel
2020-03-19  9:13 ` [PATCH 25/70] x86/sev-es: Add CPUID handling to #VC handler Joerg Roedel
2020-03-19  9:13 ` [PATCH 26/70] x86/idt: Move IDT to data segment Joerg Roedel
2020-03-19  9:13 ` [PATCH 27/70] x86/idt: Split idt_data setup out of set_intr_gate() Joerg Roedel
2020-03-19  9:13 ` [PATCH 28/70] x86/idt: Move two function from k/idt.c to i/a/desc.h Joerg Roedel
2020-03-19  9:13 ` [PATCH 29/70] x86/head/64: Install boot GDT Joerg Roedel
2020-03-19  9:13 ` [PATCH 30/70] x86/head/64: Reload GDT after switch to virtual addresses Joerg Roedel
2020-03-19  9:13 ` [PATCH 31/70] x86/head/64: Load segment registers earlier Joerg Roedel
2020-03-19  9:13 ` [PATCH 32/70] x86/head/64: Switch to initial stack earlier Joerg Roedel
2020-03-19  9:13 ` [PATCH 33/70] x86/head/64: Build k/head64.c with -fno-stack-protector Joerg Roedel
2020-03-19  9:13 ` [PATCH 34/70] x86/head/64: Load IDT earlier Joerg Roedel
2020-03-19  9:13 ` [PATCH 35/70] x86/head/64: Move early exception dispatch to C code Joerg Roedel
2020-03-19  9:13 ` [PATCH 36/70] x86/sev-es: Add SEV-ES Feature Detection Joerg Roedel
2020-03-19  9:13 ` [PATCH 37/70] x86/sev-es: Compile early handler code into kernel image Joerg Roedel
2020-03-19  9:13 ` [PATCH 38/70] x86/sev-es: Setup early #VC handler Joerg Roedel
2020-03-19  9:13 ` [PATCH 39/70] x86/sev-es: Setup GHCB based boot " Joerg Roedel
2020-03-19  9:13 ` [PATCH 40/70] x86/sev-es: Setup per-cpu GHCBs for the runtime handler Joerg Roedel
2020-04-14 19:03   ` Mike Stunes
2020-04-14 20:04     ` Tom Lendacky
2020-04-14 20:12       ` Dave Hansen
2020-04-14 20:16         ` Tom Lendacky
2020-04-14 20:18           ` Tom Lendacky
2020-04-15 15:54       ` Joerg Roedel
2020-04-15 15:53     ` Joerg Roedel
2020-04-23  1:33       ` Bo Gan
2020-04-23 11:30         ` Joerg Roedel
2020-03-19  9:13 ` [PATCH 41/70] x86/sev-es: Add Runtime #VC Exception Handler Joerg Roedel
2020-03-19 15:44   ` Andy Lutomirski
2020-03-19 16:24     ` Joerg Roedel
2020-03-19 18:43       ` Andy Lutomirski
2020-03-19 19:38         ` Joerg Roedel
2020-03-19  9:13 ` [PATCH 42/70] x86/sev-es: Support nested #VC exceptions Joerg Roedel
2020-03-19 15:46   ` Andy Lutomirski
2020-03-19 16:12     ` Joerg Roedel
2020-03-19  9:13 ` [PATCH 43/70] x86/sev-es: Wire up existing #VC exit-code handlers Joerg Roedel
2020-03-19  9:13 ` [PATCH 44/70] x86/sev-es: Handle instruction fetches from user-space Joerg Roedel
2020-03-19  9:13 ` [PATCH 45/70] x86/sev-es: Harden runtime #VC handler for exceptions " Joerg Roedel
2020-03-19  9:13 ` [PATCH 46/70] x86/sev-es: Filter exceptions not supported " Joerg Roedel
2020-03-19  9:13 ` [PATCH 47/70] x86/sev-es: Handle MMIO events Joerg Roedel
2020-03-19  9:13 ` [PATCH 48/70] x86/sev-es: Handle MMIO String Instructions Joerg Roedel
2020-03-19  9:13 ` [PATCH 49/70] x86/sev-es: Handle MSR events Joerg Roedel
2020-03-19  9:13 ` [PATCH 50/70] x86/sev-es: Handle DR7 read/write events Joerg Roedel
2020-03-19  9:13 ` [PATCH 51/70] x86/sev-es: Handle WBINVD Events Joerg Roedel
2020-03-19  9:13 ` [PATCH 52/70] x86/sev-es: Handle RDTSC Events Joerg Roedel
2020-03-19  9:13 ` [PATCH 53/70] x86/sev-es: Handle RDPMC Events Joerg Roedel
2020-03-19  9:13 ` [PATCH 54/70] x86/sev-es: Handle INVD Events Joerg Roedel
2020-03-19  9:13 ` [PATCH 55/70] x86/sev-es: Handle RDTSCP Events Joerg Roedel
2020-04-24 21:03   ` [PATCH] Allow RDTSC and RDTSCP from userspace Mike Stunes
2020-04-24 21:24     ` Dave Hansen
2020-04-24 21:27       ` Tom Lendacky
2020-04-24 22:53         ` Dave Hansen
2020-04-25 12:49           ` Joerg Roedel
2020-04-25 18:15             ` Andy Lutomirski
2020-04-25 19:10               ` Joerg Roedel
2020-04-25 19:47                 ` Andy Lutomirski
2020-04-25 20:23                   ` Joerg Roedel
2020-04-25 22:10                     ` Andy Lutomirski
2020-04-27 17:37                       ` Should SEV-ES #VC use IST? (Re: [PATCH] Allow RDTSC and RDTSCP from userspace) Andy Lutomirski
2020-04-27 18:15                         ` Andrew Cooper
2020-04-27 18:43                         ` Tom Lendacky
2020-04-28  7:55                         ` Joerg Roedel
2020-04-28 16:34                           ` Andrew Cooper
2020-06-23 11:07                           ` Peter Zijlstra
2020-06-23 11:30                             ` Joerg Roedel
2020-06-23 11:48                               ` Peter Zijlstra
2020-06-23 12:04                                 ` Joerg Roedel
2020-06-23 12:52                                   ` Peter Zijlstra
2020-06-23 13:40                                     ` Joerg Roedel
2020-06-23 13:59                                       ` Peter Zijlstra
2020-06-23 14:53                                         ` Peter Zijlstra
2020-06-23 14:59                                           ` Joerg Roedel
2020-06-23 15:23                                             ` Peter Zijlstra
2020-06-23 15:38                                               ` Peter Zijlstra
2020-06-23 15:38                                               ` Joerg Roedel
2020-06-23 16:02                                                 ` Peter Zijlstra
2020-06-23 15:39                                               ` Andrew Cooper
2020-06-23 15:52                                                 ` Peter Zijlstra
2020-06-23 16:03                                                   ` Dave Hansen
2020-06-23 16:13                                                     ` Peter Zijlstra
2020-06-23 16:13                                                 ` Borislav Petkov
2020-06-23 11:51                               ` Andrew Cooper
2020-06-23 12:47                                 ` Peter Zijlstra
2020-06-23 13:57                                   ` Andrew Cooper
2020-06-23 15:51                                 ` Borislav Petkov
2020-06-23  9:45                         ` Joerg Roedel
2020-06-23 10:45                           ` Peter Zijlstra
2020-06-23 11:11                             ` Joerg Roedel
2020-06-23 11:14                               ` Peter Zijlstra
2020-06-23 11:43                                 ` Joerg Roedel
2020-06-23 11:50                                   ` Peter Zijlstra
2020-06-23 12:12                                     ` Joerg Roedel
2020-06-23 13:03                                       ` Peter Zijlstra
2020-06-23 14:49                                         ` Joerg Roedel
2020-06-23 15:16                                           ` Peter Zijlstra
2020-06-23 15:32                                             ` Andrew Cooper
2020-06-23 16:10                                               ` Borislav Petkov
2020-06-23 15:22                                         ` Andrew Cooper
2020-06-23 18:26                                           ` Andy Lutomirski
2020-06-23 18:56                                             ` Andrew Cooper
2020-04-27 18:47             ` [PATCH] Allow RDTSC and RDTSCP from userspace Dave Hansen
2020-04-25 12:28     ` Joerg Roedel
2020-03-19  9:13 ` [PATCH 56/70] x86/sev-es: Handle MONITOR/MONITORX Events Joerg Roedel
2020-03-19  9:13 ` [PATCH 57/70] x86/sev-es: Handle MWAIT/MWAITX Events Joerg Roedel
2020-03-19  9:13 ` [PATCH 58/70] x86/sev-es: Handle VMMCALL Events Joerg Roedel
2020-03-19  9:13 ` [PATCH 59/70] x86/sev-es: Handle #AC Events Joerg Roedel
2020-03-19  9:13 ` [PATCH 60/70] x86/sev-es: Handle #DB Events Joerg Roedel
2020-03-19  9:13 ` [PATCH 61/70] x86/paravirt: Allow hypervisor specific VMMCALL handling under SEV-ES Joerg Roedel
2020-03-19  9:13 ` [PATCH 62/70] x86/kvm: Add KVM " Joerg Roedel
2020-03-20 21:23   ` David Rientjes
2020-03-20 22:21     ` Joerg Roedel
2020-03-19  9:14 ` [PATCH 63/70] x86/vmware: Add VMware specific handling for VMMCALL " Joerg Roedel
2020-03-19 10:18   ` Thomas Hellstrom
2020-03-19  9:14 ` [PATCH 64/70] x86/realmode: Add SEV-ES specific trampoline entry point Joerg Roedel
2020-03-19  9:14 ` [PATCH 65/70] x86/realmode: Setup AP jump table Joerg Roedel
2020-03-19  9:14 ` [PATCH 66/70] x86/head/64: Don't call verify_cpu() on starting APs Joerg Roedel
2020-03-19  9:14 ` [PATCH 67/70] x86/head/64: Rename start_cpu0 Joerg Roedel
2020-03-19  9:14 ` [PATCH 68/70] x86/sev-es: Support CPU offline/online Joerg Roedel
2020-03-19  9:14 ` [PATCH 69/70] x86/cpufeature: Add SEV_ES_GUEST CPU Feature Joerg Roedel
2020-03-19  9:14 ` [PATCH 70/70] x86/sev-es: Add NMI state tracking Joerg Roedel
2020-03-19 15:35   ` Andy Lutomirski
2020-03-19 16:07     ` Joerg Roedel
2020-03-19 18:40       ` Andy Lutomirski
2020-03-19 19:26         ` Joerg Roedel [this message]
2020-03-19 21:27           ` Andy Lutomirski
2020-03-20 19:48             ` Joerg Roedel
2020-03-20 13:17     ` [RFC PATCH v2.1] x86/sev-es: Handle NMI State Joerg Roedel
2020-03-20 14:42       ` Dave Hansen
2020-03-20 19:42         ` Joerg Roedel
2020-03-19 16:53   ` [PATCH 70/70] x86/sev-es: Add NMI state tracking Mika Penttilä
2020-03-19 19:41     ` Joerg Roedel

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