From: "Kuppuswamy, Sathyanarayanan" <sathyanarayanan.kuppuswamy@linux.intel.com>
To: Borislav Petkov <bp@alien8.de>
Cc: Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
Andy Lutomirski <luto@kernel.org>, Peter H Anvin <hpa@zytor.com>,
Dave Hansen <dave.hansen@intel.com>,
Tony Luck <tony.luck@intel.com>,
Dan Williams <dan.j.williams@intel.com>,
Andi Kleen <ak@linux.intel.com>,
Kirill Shutemov <kirill.shutemov@linux.intel.com>,
Sean Christopherson <seanjc@google.com>,
Kuppuswamy Sathyanarayanan <knsathya@kernel.org>,
x86@kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v5 07/12] x86/traps: Add #VE support for TDX guest
Date: Tue, 24 Aug 2021 10:32:13 -0700 [thread overview]
Message-ID: <99c5f6e9-a747-1a4a-d0f4-95b8b28e0d02@linux.intel.com> (raw)
In-Reply-To: <YSTHMAUA1LjjOQPe@zn.tnic>
On 8/24/21 3:17 AM, Borislav Petkov wrote:
> On Wed, Aug 04, 2021 at 11:13:24AM -0700, Kuppuswamy Sathyanarayanan wrote:
>> If a guest kernel action which would normally cause a #VE occurs in the
>> interrupt-disabled region before TDGETVEINFO, a #DF is delivered to the
>> guest which will result in an oops (and should eventually be a panic, as
>> we would like to set panic_on_oops to 1 for TDX guests).
>
> Who's "we"?
>
> Please use passive voice in your commit message and comments: no "we"
> or "I", etc. Personal pronouns are ambiguous in text, especially with
> so many parties/companies/etc developing the kernel so let's avoid them.
>
> Audit all your patchsets pls.
Sorry. I will fix this in next version.
>
>> Add basic infrastructure to handle any #VE which occurs in the kernel or
>> userspace. Later patches will add handling for specific #VE scenarios.
>>
>> Convert unhandled #VE's (everything, until later in this series) so that
>> they appear just like a #GP by calling ve_raise_fault() directly.
>> ve_raise_fault() is similar to #GP handler and is responsible for
>> sending SIGSEGV to userspace and cpu die and notifying debuggers and
>
> In all your text:
>
> s/cpu/CPU/g
>
> Audit all your patchsets pls.
Yes. I will fix this in next version.
>
>> @@ -53,6 +67,11 @@ u64 __tdx_module_call(u64 fn, u64 rcx, u64 rdx, u64 r8, u64 r9,
>> u64 __tdx_hypercall(u64 type, u64 fn, u64 r12, u64 r13, u64 r14,
>> u64 r15, struct tdx_hypercall_output *out);
>>
>> +unsigned long tdg_get_ve_info(struct ve_info *ve);
>> +
>> +int tdg_handle_virtualization_exception(struct pt_regs *regs,
>
> There's that "tdg" prefix again. Please fix all your patchsets.
Mainly chose it avoid future name conflicts with KVM (tdx) calls. But
if you don't like "tdg", I can change it back to "tdx" and resolve the
naming issues when it occurs.
>> static struct {
>> unsigned int gpa_width;
>> @@ -75,6 +76,41 @@ static void tdg_get_info(void)
>> td_info.attributes = out.rdx;
>> }
>>
>> +unsigned long tdg_get_ve_info(struct ve_info *ve)
>> +{
>> + u64 ret;
>> + struct tdx_module_output out = {0};
>
> The tip-tree preferred ordering of variable declarations at the
> beginning of a function is reverse fir tree order::
>
> struct long_struct_name *descriptive_name;
> unsigned long foo, bar;
> unsigned int tmp;
> int ret;
>
> The above is faster to parse than the reverse ordering::
>
> int ret;
> unsigned int tmp;
> unsigned long foo, bar;
> struct long_struct_name *descriptive_name;
>
> And even more so than random ordering::
>
> unsigned long foo, bar;
> int ret;
> struct long_struct_name *descriptive_name;
> unsigned int tmp;
Yes. I will fix this in next version.
>> +int tdg_handle_virtualization_exception(struct pt_regs *regs,
>> + struct ve_info *ve)
>> +{
>> + /*
>> + * TODO: Add handler support for various #VE exit
>> + * reasons. It will be added by other patches in
>> + * the series.
>> + */
>
> That comment needs to go.
Ok. I will remove it.
>> +#ifdef CONFIG_INTEL_TDX_GUEST
>> +#define VEFSTR "VE fault"
>> +static void ve_raise_fault(struct pt_regs *regs, long error_code)
>> +{
>> + struct task_struct *tsk = current;
>> +
>> + if (user_mode(regs)) {
>> + tsk->thread.error_code = error_code;
>> + tsk->thread.trap_nr = X86_TRAP_VE;
>> +
>> + /*
>> + * Not fixing up VDSO exceptions similar to #GP handler
>> + * because we don't expect the VDSO to trigger #VE.
>> + */
>> + show_signal(tsk, SIGSEGV, "", VEFSTR, regs, error_code);
>> + force_sig(SIGSEGV);
>> + return;
>> + }
>> +
>> + if (fixup_exception(regs, X86_TRAP_VE, error_code, 0))
>
> There are exception table entries which can trigger a #VE?
It is required to handle #VE exceptions raised by unhandled MSR
read/writes.
>
>> + return;
>> +
>> + tsk->thread.error_code = error_code;
>> + tsk->thread.trap_nr = X86_TRAP_VE;
>> +
>> + /*
>> + * To be potentially processing a kprobe fault and to trust the result
>> + * from kprobe_running(), we have to be non-preemptible.
>> + */
>> + if (!preemptible() &&
>> + kprobe_running() &&
>> + kprobe_fault_handler(regs, X86_TRAP_VE))
>> + return;
>> +
>> + notify_die(DIE_GPF, VEFSTR, regs, error_code, X86_TRAP_VE, SIGSEGV);
>
> Other handlers check that retval.
Ok. I can check it. But there is only one statement after this call. So it
may not be very helpful.
>
--
Sathyanarayanan Kuppuswamy
Linux Kernel Developer
next prev parent reply other threads:[~2021-08-24 17:43 UTC|newest]
Thread overview: 72+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-04 18:13 [PATCH v5 00/12] Add TDX Guest Support (Initial support) Kuppuswamy Sathyanarayanan
2021-08-04 18:13 ` [PATCH v5 01/12] x86/paravirt: Move halt paravirt calls under CONFIG_PARAVIRT Kuppuswamy Sathyanarayanan
2021-08-12 7:18 ` Borislav Petkov
2021-08-12 17:17 ` Kuppuswamy, Sathyanarayanan
2021-08-17 12:50 ` Juergen Gross
2021-08-17 13:16 ` Kuppuswamy, Sathyanarayanan
2021-08-17 13:28 ` Juergen Gross
2021-08-17 13:39 ` Kuppuswamy, Sathyanarayanan
2021-08-17 13:47 ` Juergen Gross
2021-08-17 13:50 ` Kuppuswamy, Sathyanarayanan
2021-08-04 18:13 ` [PATCH v5 02/12] x86/tdx: Introduce INTEL_TDX_GUEST config option Kuppuswamy Sathyanarayanan
2021-08-04 18:13 ` [PATCH v5 03/12] x86/cpufeatures: Add TDX Guest CPU feature Kuppuswamy Sathyanarayanan
2021-08-12 7:39 ` Borislav Petkov
2021-08-04 18:13 ` [PATCH v5 04/12] x86/tdx: Add protected guest support for TDX guest Kuppuswamy Sathyanarayanan
2021-08-04 21:59 ` Sean Christopherson
2021-08-04 22:03 ` Dave Hansen
2021-08-04 22:26 ` Kuppuswamy, Sathyanarayanan
2021-08-04 22:42 ` Sean Christopherson
2021-08-04 23:00 ` Kuppuswamy, Sathyanarayanan
2021-08-12 7:53 ` Borislav Petkov
2021-08-12 17:18 ` Kuppuswamy, Sathyanarayanan
2021-08-20 14:28 ` Borislav Petkov
2021-08-20 16:42 ` Kuppuswamy, Sathyanarayanan
2021-08-20 16:59 ` Borislav Petkov
2021-08-20 17:11 ` Kuppuswamy, Sathyanarayanan
2021-08-04 18:13 ` [PATCH v5 05/12] x86/tdx: Add __tdx_module_call() and __tdx_hypercall() helper functions Kuppuswamy Sathyanarayanan
2021-08-20 15:16 ` Borislav Petkov
2021-08-04 18:13 ` [PATCH v5 06/12] x86/tdx: Get TD execution environment information via TDINFO Kuppuswamy Sathyanarayanan
2021-08-04 22:38 ` Sean Christopherson
2021-08-20 17:13 ` Borislav Petkov
2021-08-20 17:31 ` Kuppuswamy, Sathyanarayanan
2021-08-20 17:35 ` Borislav Petkov
2021-08-20 18:29 ` Kuppuswamy, Sathyanarayanan
2021-08-20 18:58 ` Andi Kleen
2021-08-20 19:01 ` Kuppuswamy, Sathyanarayanan
2021-08-04 18:13 ` [PATCH v5 07/12] x86/traps: Add #VE support for TDX guest Kuppuswamy Sathyanarayanan
2021-08-24 10:17 ` Borislav Petkov
2021-08-24 17:32 ` Kuppuswamy, Sathyanarayanan [this message]
2021-08-24 17:36 ` Dave Hansen
2021-08-24 17:46 ` Borislav Petkov
2021-09-02 15:24 ` Kuppuswamy, Sathyanarayanan
2021-09-03 10:17 ` Borislav Petkov
2021-08-04 18:13 ` [PATCH v5 08/12] x86/tdx: Add HLT " Kuppuswamy Sathyanarayanan
2021-08-24 16:10 ` Borislav Petkov
2021-08-24 17:06 ` Sean Christopherson
2021-08-24 17:25 ` Andi Kleen
2021-08-24 17:27 ` Borislav Petkov
2021-08-24 17:47 ` Sean Christopherson
2021-08-24 17:50 ` Borislav Petkov
2021-08-31 20:49 ` Kuppuswamy, Sathyanarayanan
2021-09-01 7:42 ` Borislav Petkov
2021-08-24 18:18 ` Kuppuswamy, Sathyanarayanan
2021-08-24 18:28 ` Andi Kleen
2021-08-24 17:35 ` Kuppuswamy, Sathyanarayanan
2021-08-24 17:48 ` Borislav Petkov
2021-08-04 18:13 ` [PATCH v5 09/12] x86/tdx: Wire up KVM hypercalls Kuppuswamy Sathyanarayanan
2021-08-24 16:34 ` Borislav Petkov
2021-08-24 18:11 ` Kuppuswamy, Sathyanarayanan
2021-08-24 18:29 ` Borislav Petkov
2021-08-24 19:11 ` Kuppuswamy, Sathyanarayanan
2021-08-24 19:39 ` Borislav Petkov
2021-08-04 18:13 ` [PATCH v5 10/12] x86/tdx: Add MSR support for TDX guest Kuppuswamy Sathyanarayanan
2021-08-24 16:55 ` Borislav Petkov
2021-08-24 18:12 ` Kuppuswamy, Sathyanarayanan
2021-08-04 18:13 ` [PATCH v5 11/12] x86/tdx: Don't write CSTAR MSR on Intel Kuppuswamy Sathyanarayanan
2021-08-04 18:31 ` Sean Christopherson
2021-08-04 21:03 ` Kuppuswamy, Sathyanarayanan
2021-08-04 21:44 ` Sean Christopherson
2021-08-04 21:48 ` Dave Hansen
2021-08-04 22:23 ` Kuppuswamy, Sathyanarayanan
2021-08-04 18:13 ` [PATCH v5 12/12] x86/tdx: Handle CPUID via #VE Kuppuswamy Sathyanarayanan
2021-08-24 17:48 ` Borislav Petkov
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