From: Joerg Roedel <joro@8bytes.org>
To: Lai Jiangshan <jiangshanlai+lkml@gmail.com>
Cc: Juergen Gross <jgross@suse.com>,
Tom Lendacky <thomas.lendacky@amd.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
Mike Stunes <mstunes@vmware.com>,
Kees Cook <keescook@chromium.org>,
kvm@vger.kernel.org, Peter Zijlstra <peterz@infradead.org>,
Cfir Cohen <cfir@google.com>, X86 ML <x86@kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
Sean Christopherson <sean.j.christopherson@intel.com>,
virtualization@lists.linux-foundation.org,
Martin Radev <martin.b.radev@gmail.com>,
Joerg Roedel <jroedel@suse.de>,
Masami Hiramatsu <mhiramat@kernel.org>,
Andy Lutomirski <luto@kernel.org>,
"H. Peter Anvin" <hpa@zytor.com>,
Erdem Aktas <erdemaktas@google.com>,
David Rientjes <rientjes@google.com>,
Dan Williams <dan.j.williams@intel.com>,
Jiri Slaby <jslaby@suse.cz>
Subject: Re: [PATCH v7 45/72] x86/entry/64: Add entry code for #VC handler
Date: Thu, 28 Jan 2021 14:18:18 +0100 [thread overview]
Message-ID: <20210128131817.GP32671@8bytes.org> (raw)
In-Reply-To: <CAJhGHyCMMCY9bZauzrSeQr_62SpJgZQEQy9P7Rh28HXJtF5O5A@mail.gmail.com>
Hello Lai,
On Sun, Jan 24, 2021 at 10:11:14PM +0800, Lai Jiangshan wrote:
> > +
> > + /*
> > + * No need to switch back to the IST stack. The current stack is either
> > + * identical to the stack in the IRET frame or the VC fall-back stack,
> > + * so it is definitly mapped even with PTI enabled.
> > + */
> > + jmp paranoid_exit
> > +
> >
>
> Hello
>
> I know we don't enable PTI on AMD, but the above comment doesn't align to the
> next code.
>
> We assume PTI is enabled as the comments said "even with PTI enabled".
>
> When #VC happens after entry_SYSCALL_64 but before it switches to the
> kernel CR3. vc_switch_off_ist() will switch the stack to the kernel stack
> and paranoid_exit can't work when it switches to user CR3 on the kernel stack.
>
> The comment above lost information that the current stack is possible to be
> the kernel stack which is mapped not user CR3.
>
> Maybe I missed something.
You are right, the scenario above would cause problems for the current
#VC entry code. With SEV-ES an #VC exception can't happen in the early
syscall entry code, so I think its the best to update the comment
reflecting this.
In the future this might change and then the #VC entry code needs to
take care of this case too. Thanks for pointing it out.
Regards,
Joerg
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next prev parent reply other threads:[~2021-01-28 13:18 UTC|newest]
Thread overview: 89+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-07 13:15 [PATCH v7 00/72] x86: SEV-ES Guest Support Joerg Roedel
2020-09-07 13:15 ` [PATCH v7 01/72] KVM: SVM: nested: Don't allocate VMCB structures on stack Joerg Roedel
[not found] ` <160459347763.31546.3911053208379939674@vm0>
2020-11-05 16:38 ` Borislav Petkov
[not found] ` <20201106003153.wrr7zvjjl3hl2pec@vm0>
2020-11-06 0:39 ` Borislav Petkov
2020-09-07 13:15 ` [PATCH v7 02/72] KVM: SVM: Add GHCB definitions Joerg Roedel
2020-09-07 13:15 ` [PATCH v7 03/72] KVM: SVM: Add GHCB Accessor functions Joerg Roedel
2020-09-07 13:15 ` [PATCH v7 04/72] KVM: SVM: Use __packed shorthand Joerg Roedel
2020-09-07 13:15 ` [PATCH v7 05/72] x86/cpufeatures: Add SEV-ES CPU feature Joerg Roedel
2020-09-07 13:15 ` [PATCH v7 06/72] x86/traps: Move pf error codes to <asm/trap_pf.h> Joerg Roedel
2020-09-07 13:15 ` [PATCH v7 07/72] x86/insn: Make inat-tables.c suitable for pre-decompression code Joerg Roedel
2020-09-07 13:15 ` [PATCH v7 08/72] x86/umip: Factor out instruction fetch Joerg Roedel
2020-09-07 13:15 ` [PATCH v7 09/72] x86/umip: Factor out instruction decoding Joerg Roedel
2020-09-07 13:15 ` [PATCH v7 10/72] x86/insn: Add insn_get_modrm_reg_off() Joerg Roedel
2020-09-07 13:15 ` [PATCH v7 11/72] x86/insn: Add insn_has_rep_prefix() helper Joerg Roedel
2020-09-07 13:15 ` [PATCH v7 12/72] x86/boot/compressed/64: Disable red-zone usage Joerg Roedel
2020-09-07 13:15 ` [PATCH v7 13/72] x86/boot/compressed/64: Add IDT Infrastructure Joerg Roedel
2020-09-07 13:15 ` [PATCH v7 14/72] x86/boot/compressed/64: Rename kaslr_64.c to ident_map_64.c Joerg Roedel
2020-09-07 13:15 ` [PATCH v7 15/72] x86/boot/compressed/64: Add page-fault handler Joerg Roedel
2020-09-07 13:15 ` [PATCH v7 16/72] x86/boot/compressed/64: Always switch to own page-table Joerg Roedel
2020-09-07 13:15 ` [PATCH v7 17/72] x86/boot/compressed/64: Don't pre-map memory in KASLR code Joerg Roedel
2020-09-07 13:15 ` [PATCH v7 18/72] x86/boot/compressed/64: Change add_identity_map() to take start and end Joerg Roedel
2020-09-07 13:15 ` [PATCH v7 19/72] x86/boot/compressed/64: Add stage1 #VC handler Joerg Roedel
2020-09-07 16:58 ` Borislav Petkov
2020-09-07 13:15 ` [PATCH v7 20/72] x86/boot/compressed/64: Call set_sev_encryption_mask() earlier Joerg Roedel
2020-09-07 13:15 ` [PATCH v7 21/72] x86/boot/compressed/64: Check return value of kernel_ident_mapping_init() Joerg Roedel
2020-09-07 13:15 ` [PATCH v7 22/72] x86/boot/compressed/64: Add set_page_en/decrypted() helpers Joerg Roedel
2020-09-07 13:15 ` [PATCH v7 23/72] x86/boot/compressed/64: Setup GHCB Based VC Exception handler Joerg Roedel
2020-09-07 13:15 ` [PATCH v7 24/72] x86/boot/compressed/64: Unmap GHCB page before booting the kernel Joerg Roedel
2020-09-07 13:15 ` [PATCH v7 25/72] x86/sev-es: Add support for handling IOIO exceptions Joerg Roedel
2020-09-07 13:15 ` [PATCH v7 26/72] x86/fpu: Move xgetbv()/xsetbv() into separate header Joerg Roedel
2020-09-07 13:15 ` [PATCH v7 27/72] x86/sev-es: Add CPUID handling to #VC handler Joerg Roedel
2020-09-07 13:15 ` [PATCH v7 28/72] x86/idt: Split idt_data setup out of set_intr_gate() Joerg Roedel
2020-09-07 13:15 ` [PATCH v7 29/72] x86/head/64: Install startup GDT Joerg Roedel
2020-09-07 13:15 ` [PATCH v7 30/72] x86/head/64: Load GDT after switch to virtual addresses Joerg Roedel
2020-09-07 13:15 ` [PATCH v7 31/72] x86/head/64: Load segment registers earlier Joerg Roedel
2020-09-07 13:15 ` [PATCH v7 32/72] x86/head/64: Switch to initial stack earlier Joerg Roedel
2020-09-07 13:15 ` [PATCH v7 33/72] x86/head/64: Install a CPU bringup IDT Joerg Roedel
2020-09-07 13:15 ` [PATCH v7 34/72] x86/idt: Move two function from k/idt.c to i/a/desc.h Joerg Roedel
2020-09-07 13:15 ` [PATCH v7 35/72] x86/head/64: Move early exception dispatch to C code Joerg Roedel
2020-09-07 13:15 ` [PATCH v7 36/72] x86/sev-es: Add SEV-ES Feature Detection Joerg Roedel
2020-09-07 21:02 ` Borislav Petkov
2020-09-07 13:15 ` [PATCH v7 37/72] x86/sev-es: Print SEV-ES info into kernel log Joerg Roedel
2020-09-07 13:15 ` [PATCH v7 38/72] x86/sev-es: Compile early handler code into kernel image Joerg Roedel
2020-09-07 13:15 ` [PATCH v7 39/72] x86/sev-es: Setup early #VC handler Joerg Roedel
2020-09-08 10:22 ` [PATCH v7.1 " Joerg Roedel
2020-09-08 12:35 ` [PATCH v7.2 39/74] " Joerg Roedel
2020-09-07 13:15 ` [PATCH v7 40/72] x86/sev-es: Setup GHCB based boot " Joerg Roedel
2020-09-08 10:24 ` [PATCH v7.1 " Joerg Roedel
2020-09-08 12:38 ` [PATCH v7.2 40/74] " Joerg Roedel
2020-09-07 13:15 ` [PATCH v7 41/72] x86/sev-es: Setup per-cpu GHCBs for the runtime handler Joerg Roedel
2020-09-08 10:51 ` Borislav Petkov
2020-09-07 13:15 ` [PATCH v7 42/72] x86/sev-es: Allocate and Map IST stack for #VC handler Joerg Roedel
2020-09-07 13:15 ` [PATCH v7 43/72] x86/sev-es: Adjust #VC IST Stack on entering NMI handler Joerg Roedel
2020-09-07 13:15 ` [PATCH v7 44/72] x86/dumpstack/64: Add noinstr version of get_stack_info() Joerg Roedel
2020-09-07 13:15 ` [PATCH v7 45/72] x86/entry/64: Add entry code for #VC handler Joerg Roedel
[not found] ` <CAJhGHyCMMCY9bZauzrSeQr_62SpJgZQEQy9P7Rh28HXJtF5O5A@mail.gmail.com>
2021-01-28 13:18 ` Joerg Roedel [this message]
2020-09-07 13:15 ` [PATCH v7 46/72] x86/sev-es: Add Runtime #VC Exception Handler Joerg Roedel
2020-09-07 13:15 ` [PATCH v7 47/72] x86/sev-es: Wire up existing #VC exit-code handlers Joerg Roedel
2020-09-07 13:15 ` [PATCH v7 48/72] x86/sev-es: Handle instruction fetches from user-space Joerg Roedel
2020-09-07 13:15 ` [PATCH v7 49/72] x86/sev-es: Handle MMIO events Joerg Roedel
2020-09-07 13:15 ` [PATCH v7 50/72] x86/sev-es: Handle MMIO String Instructions Joerg Roedel
2020-09-07 13:15 ` [PATCH v7 51/72] x86/sev-es: Handle MSR events Joerg Roedel
2020-09-07 13:15 ` [PATCH v7 52/72] x86/sev-es: Handle DR7 read/write events Joerg Roedel
2020-09-07 13:15 ` [PATCH v7 53/72] x86/sev-es: Handle WBINVD Events Joerg Roedel
2020-09-07 13:15 ` [PATCH v7 54/72] x86/sev-es: Handle RDTSC(P) Events Joerg Roedel
2020-09-07 13:15 ` [PATCH v7 55/72] x86/sev-es: Handle RDPMC Events Joerg Roedel
2020-09-07 13:15 ` [PATCH v7 56/72] x86/sev-es: Handle INVD Events Joerg Roedel
2020-09-07 13:15 ` [PATCH v7 57/72] x86/sev-es: Handle MONITOR/MONITORX Events Joerg Roedel
2020-09-07 13:15 ` [PATCH v7 58/72] x86/sev-es: Handle MWAIT/MWAITX Events Joerg Roedel
2020-09-07 13:16 ` [PATCH v7 59/72] x86/sev-es: Handle VMMCALL Events Joerg Roedel
2020-09-07 13:16 ` [PATCH v7 60/72] x86/sev-es: Handle #AC Events Joerg Roedel
2020-09-07 13:16 ` [PATCH v7 61/72] x86/sev-es: Handle #DB Events Joerg Roedel
2020-09-07 13:16 ` [PATCH v7 62/72] x86/paravirt: Allow hypervisor specific VMMCALL handling under SEV-ES Joerg Roedel
2020-09-07 13:16 ` [PATCH v7 63/72] x86/kvm: Add KVM " Joerg Roedel
2020-09-07 13:16 ` [PATCH v7 64/72] x86/vmware: Add VMware specific handling for VMMCALL " Joerg Roedel
2020-09-07 13:16 ` [PATCH v7 65/72] x86/realmode: Add SEV-ES specific trampoline entry point Joerg Roedel
2020-09-07 13:16 ` [PATCH v7 66/72] x86/realmode: Setup AP jump table Joerg Roedel
2020-09-07 13:16 ` [PATCH v7 67/72] x86/smpboot: Load TSS and getcpu GDT entry before loading IDT Joerg Roedel
2020-09-08 17:20 ` Borislav Petkov
2020-09-08 18:42 ` Joerg Roedel
2020-09-07 13:16 ` [PATCH v7 68/72] x86/head/64: Don't call verify_cpu() on starting APs Joerg Roedel
2020-09-07 13:16 ` [PATCH v7 69/72] x86/sev-es: Support CPU offline/online Joerg Roedel
2020-09-07 13:16 ` [PATCH v7 70/72] x86/sev-es: Handle NMI State Joerg Roedel
2020-09-07 13:16 ` [PATCH v7 71/72] x86/efi: Add GHCB mappings when SEV-ES is active Joerg Roedel
2020-09-08 17:46 ` Borislav Petkov
[not found] ` <CAMj1kXHbePrDYXGbVG0fHfH5=M19ZpCLm9YVTs-yKTuR_jFLDg@mail.gmail.com>
2020-09-09 12:44 ` Laszlo Ersek
2020-09-09 13:24 ` Laszlo Ersek
2020-09-09 13:49 ` Tom Lendacky
2020-09-07 13:16 ` [PATCH v7 72/72] x86/sev-es: Check required CPU features for SEV-ES Joerg Roedel
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