From: Brijesh Singh <brijesh.singh@amd.com>
To: Borislav Petkov <bp@alien8.de>, Vlastimil Babka <vbabka@suse.cz>
Cc: brijesh.singh@amd.com, x86@kernel.org,
linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
linux-efi@vger.kernel.org, platform-driver-x86@vger.kernel.org,
linux-coco@lists.linux.dev, linux-mm@kvack.org,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Joerg Roedel <jroedel@suse.de>,
Tom Lendacky <thomas.lendacky@amd.com>,
"H. Peter Anvin" <hpa@zytor.com>,
Ard Biesheuvel <ardb@kernel.org>,
Paolo Bonzini <pbonzini@redhat.com>,
Sean Christopherson <seanjc@google.com>,
Vitaly Kuznetsov <vkuznets@redhat.com>,
Jim Mattson <jmattson@google.com>,
Andy Lutomirski <luto@kernel.org>,
Dave Hansen <dave.hansen@linux.intel.com>,
Sergio Lopez <slp@redhat.com>, Peter Gonda <pgonda@google.com>,
Peter Zijlstra <peterz@infradead.org>,
Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>,
David Rientjes <rientjes@google.com>,
Dov Murik <dovmurik@linux.ibm.com>,
Tobin Feldman-Fitzthum <tobin@ibm.com>,
Michael Roth <michael.roth@amd.com>,
"Kirill A . Shutemov" <kirill@shutemov.name>,
Andi Kleen <ak@linux.intel.com>,
"Dr . David Alan Gilbert" <dgilbert@redhat.com>,
tony.luck@intel.com, marcorr@google.com,
sathyanarayanan.kuppuswamy@linux.intel.com
Subject: Re: [PATCH v8 20/40] x86/sev: Use SEV-SNP AP creation to start secondary CPUs
Date: Wed, 12 Jan 2022 10:33:40 -0600 [thread overview]
Message-ID: <75c0605f-7ed0-abcc-4855-dae5d87d0861@amd.com> (raw)
In-Reply-To: <Yc8jerEP5CrxfFi4@zn.tnic>
On 12/31/21 9:36 AM, Borislav Petkov wrote:
> On Fri, Dec 10, 2021 at 09:43:12AM -0600, Brijesh Singh wrote:
>> diff --git a/arch/x86/include/asm/sev-common.h b/arch/x86/include/asm/sev-common.h
>> index 123a96f7dff2..38c14601ae4a 100644
>> --- a/arch/x86/include/asm/sev-common.h
>> +++ b/arch/x86/include/asm/sev-common.h
>> @@ -104,6 +104,7 @@ enum psc_op {
>> (((u64)(v) & GENMASK_ULL(63, 12)) >> 12)
>>
>> #define GHCB_HV_FT_SNP BIT_ULL(0)
>> +#define GHCB_HV_FT_SNP_AP_CREATION (BIT_ULL(1) | GHCB_HV_FT_SNP)
>
> Why is bit 0 ORed in? Because it "Requires SEV-SNP Feature."?
>
Yes, the SEV-SNP feature is required. Anyway, I will improve a check. We
will reach to AP creation only after SEV-SNP feature is checked, so, in
AP creation routine we just need to check for the AP_CREATION specific
feature flag; I will add comment about it.
> You can still enforce that requirement in the test though.
>
> Or all those SEV features should not be bits but masks -
> GHCB_HV_FT_SNP_AP_CREATION_MASK for example, seeing how the others
> require the previous bits to be set too.
>
> ...
>
>> static DEFINE_PER_CPU(struct sev_es_runtime_data*, runtime_data);
>> DEFINE_STATIC_KEY_FALSE(sev_es_enable_key);
>>
>> +static DEFINE_PER_CPU(struct sev_es_save_area *, snp_vmsa);
>
> This is what I mean: the struct is called "sev_es... " but the variable
> "snp_...". I.e., it is all sev_<something>.
>
Sure, I define the variable as sev_vmsa.
>> +
>> static __always_inline bool on_vc_stack(struct pt_regs *regs)
>> {
>> unsigned long sp = regs->sp;
>> @@ -814,6 +818,231 @@ void snp_set_memory_private(unsigned long vaddr, unsigned int npages)
>> pvalidate_pages(vaddr, npages, 1);
>> }
>>
>> +static int snp_set_vmsa(void *va, bool vmsa)
>> +{
>> + u64 attrs;
>> +
>> + /*
>> + * The RMPADJUST instruction is used to set or clear the VMSA bit for
>> + * a page. A change to the VMSA bit is only performed when running
>> + * at VMPL0 and is ignored at other VMPL levels. If too low of a target
>
> What does "too low" mean here exactly?
>
I believe its saying that target VMPL is lesser than the current VMPL
level. Now that we have VMPL0 check enforced in the beginning so will
work on improving comment.
> The kernel is not at VMPL0 but the specified level is lower? Weird...
>
>> + * VMPL level is specified, the instruction can succeed without changing
>> + * the VMSA bit should the kernel not be in VMPL0. Using a target VMPL
>> + * level of 1 will return a FAIL_PERMISSION error if the kernel is not
>> + * at VMPL0, thus ensuring that the VMSA bit has been properly set when
>> + * no error is returned.
>
> We do check whether we run at VMPL0 earlier when starting the guest -
> see enforce_vmpl0().
>
> I don't think you need any of that additional verification here - just
> assume you are at VMPL0.
>
Yep.
>> + */
>> + attrs = 1;
>> + if (vmsa)
>> + attrs |= RMPADJUST_VMSA_PAGE_BIT;
>> +
>> + return rmpadjust((unsigned long)va, RMP_PG_SIZE_4K, attrs);
>> +}
>> +
>> +#define __ATTR_BASE (SVM_SELECTOR_P_MASK | SVM_SELECTOR_S_MASK)
>> +#define INIT_CS_ATTRIBS (__ATTR_BASE | SVM_SELECTOR_READ_MASK | SVM_SELECTOR_CODE_MASK)
>> +#define INIT_DS_ATTRIBS (__ATTR_BASE | SVM_SELECTOR_WRITE_MASK)
>> +
>> +#define INIT_LDTR_ATTRIBS (SVM_SELECTOR_P_MASK | 2)
>> +#define INIT_TR_ATTRIBS (SVM_SELECTOR_P_MASK | 3)
>> +
>> +static void *snp_safe_alloc_page(void)
>
> safe?
>
> And you don't need to say "safe" - snp_alloc_vmsa_page() is perfectly fine.
>
noted.
...
>> +
>> + /*
>> + * A new VMSA is created each time because there is no guarantee that
>> + * the current VMSA is the kernels or that the vCPU is not running. If
>
> kernel's.
>
> And if it is not the kernel's, whose it is?
It could be hypervisor's VMSA.
>
>> + * an attempt was done to use the current VMSA with a running vCPU, a
>> + * #VMEXIT of that vCPU would wipe out all of the settings being done
>> + * here.
>
> I don't understand - this is waking up a CPU, how can it ever be a
> running vCPU which is using the current VMSA?!
>
> There is per_cpu(snp_vmsa, cpu), who else can be using that one currently?
>
Maybe Tom can expand it bit more?
...
>> +
>> + if (!ghcb_sw_exit_info_1_is_valid(ghcb) ||
>> + lower_32_bits(ghcb->save.sw_exit_info_1)) {
>> + pr_alert("SNP AP Creation error\n");
>
> alert?
I see that smboot.c is using the pr_err() when failing to wakeup CPU;
will switch to pr_err(), let me know if you don't agree with it.
thx
next prev parent reply other threads:[~2022-01-12 16:33 UTC|newest]
Thread overview: 183+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-10 15:42 [PATCH v8 00/40] Add AMD Secure Nested Paging (SEV-SNP) Guest Support Brijesh Singh
2021-12-10 15:42 ` [PATCH v8 01/40] x86/compressed/64: detect/setup SEV/SME features earlier in boot Brijesh Singh
2021-12-10 18:47 ` Dave Hansen
2021-12-10 19:12 ` Borislav Petkov
2021-12-10 19:23 ` Dave Hansen
2021-12-10 19:33 ` Borislav Petkov
2021-12-13 19:09 ` Venu Busireddy
2021-12-13 19:17 ` Borislav Petkov
2021-12-14 17:46 ` Venu Busireddy
2021-12-14 19:10 ` Borislav Petkov
2021-12-15 0:14 ` Venu Busireddy
2021-12-15 11:57 ` Borislav Petkov
2021-12-15 14:43 ` Tom Lendacky
2021-12-15 17:49 ` Michael Roth
2021-12-15 18:17 ` Venu Busireddy
2021-12-15 18:33 ` Borislav Petkov
2021-12-15 20:17 ` Michael Roth
2021-12-15 20:38 ` Borislav Petkov
2021-12-15 21:22 ` Michael Roth
2022-01-03 19:10 ` Venu Busireddy
2022-01-05 19:34 ` Brijesh Singh
2022-01-10 20:46 ` Brijesh Singh
2022-01-10 21:17 ` Venu Busireddy
2022-01-10 21:38 ` Borislav Petkov
2021-12-15 20:43 ` Michael Roth
2021-12-15 19:54 ` Venu Busireddy
2021-12-15 18:58 ` Venu Busireddy
2021-12-15 17:51 ` Michael Roth
2021-12-10 15:42 ` [PATCH v8 02/40] x86/sev: " Brijesh Singh
2021-12-13 22:36 ` Venu Busireddy
2021-12-10 15:42 ` [PATCH v8 03/40] x86/mm: Extend cc_attr to include AMD SEV-SNP Brijesh Singh
2021-12-13 22:47 ` Venu Busireddy
2021-12-14 15:53 ` Borislav Petkov
2021-12-10 15:42 ` [PATCH v8 04/40] x86/sev: Define the Linux specific guest termination reasons Brijesh Singh
2021-12-14 0:13 ` Venu Busireddy
2021-12-14 22:22 ` Borislav Petkov
2021-12-10 15:42 ` [PATCH v8 05/40] x86/sev: Save the negotiated GHCB version Brijesh Singh
2021-12-14 0:32 ` Venu Busireddy
2021-12-10 15:42 ` [PATCH v8 06/40] x86/sev: Check SEV-SNP features support Brijesh Singh
2021-12-16 15:47 ` Borislav Petkov
2021-12-16 16:28 ` Brijesh Singh
2021-12-16 16:58 ` Borislav Petkov
2021-12-16 19:01 ` Venu Busireddy
2021-12-10 15:42 ` [PATCH v8 07/40] x86/sev: Add a helper for the PVALIDATE instruction Brijesh Singh
2021-12-16 20:20 ` Venu Busireddy
2021-12-10 15:43 ` [PATCH v8 08/40] x86/sev: Check the vmpl level Brijesh Singh
2021-12-16 20:24 ` Venu Busireddy
2021-12-16 23:39 ` Mikolaj Lisik
2021-12-17 22:19 ` Brijesh Singh
2021-12-17 22:33 ` Tom Lendacky
2021-12-20 18:10 ` Borislav Petkov
2022-01-04 15:23 ` Brijesh Singh
2021-12-10 15:43 ` [PATCH v8 09/40] x86/compressed: Add helper for validating pages in the decompression stage Brijesh Singh
2021-12-17 20:47 ` Venu Busireddy
2021-12-17 23:24 ` Brijesh Singh
2022-01-03 18:43 ` Venu Busireddy
2021-12-21 13:01 ` Borislav Petkov
2021-12-10 15:43 ` [PATCH v8 10/40] x86/compressed: Register GHCB memory when SEV-SNP is active Brijesh Singh
2022-01-03 19:54 ` Venu Busireddy
2021-12-10 15:43 ` [PATCH v8 11/40] x86/sev: " Brijesh Singh
2021-12-22 13:16 ` Borislav Petkov
2021-12-22 15:16 ` Brijesh Singh
2022-01-03 22:47 ` Venu Busireddy
2021-12-10 15:43 ` [PATCH v8 12/40] x86/sev: Add helper for validating pages in early enc attribute changes Brijesh Singh
2021-12-23 11:50 ` Borislav Petkov
2022-01-04 15:33 ` Brijesh Singh
2022-01-03 23:28 ` Venu Busireddy
2022-01-11 21:22 ` Brijesh Singh
2022-01-11 21:51 ` Venu Busireddy
2022-01-11 21:57 ` Brijesh Singh
2022-01-11 22:42 ` Venu Busireddy
2021-12-10 15:43 ` [PATCH v8 13/40] x86/kernel: Make the bss.decrypted section shared in RMP table Brijesh Singh
2021-12-28 11:53 ` Borislav Petkov
2022-01-04 17:56 ` Venu Busireddy
2022-01-05 19:52 ` Brijesh Singh
2022-01-05 20:27 ` Dave Hansen
2022-01-05 21:39 ` Brijesh Singh
2022-01-06 17:40 ` Venu Busireddy
2022-01-06 19:06 ` Tom Lendacky
2022-01-06 20:16 ` Venu Busireddy
2022-01-06 20:50 ` Tom Lendacky
2021-12-10 15:43 ` [PATCH v8 14/40] x86/kernel: Validate rom memory before accessing when SEV-SNP is active Brijesh Singh
2021-12-28 15:40 ` Borislav Petkov
2021-12-10 15:43 ` [PATCH v8 15/40] x86/mm: Add support to validate memory when changing C-bit Brijesh Singh
2021-12-29 11:09 ` Borislav Petkov
2022-01-04 22:31 ` Venu Busireddy
2021-12-10 15:43 ` [PATCH v8 16/40] KVM: SVM: Define sev_features and vmpl field in the VMSA Brijesh Singh
2022-01-04 22:59 ` Venu Busireddy
2021-12-10 15:43 ` [PATCH v8 17/40] KVM: SVM: Create a separate mapping for the SEV-ES save area Brijesh Singh
2021-12-30 12:19 ` Borislav Petkov
2022-01-05 1:38 ` Venu Busireddy
2021-12-10 15:43 ` [PATCH v8 18/40] KVM: SVM: Create a separate mapping for the GHCB " Brijesh Singh
2022-01-05 18:41 ` Venu Busireddy
2021-12-10 15:43 ` [PATCH v8 19/40] KVM: SVM: Update the SEV-ES save area mapping Brijesh Singh
2022-01-05 18:54 ` Venu Busireddy
2021-12-10 15:43 ` [PATCH v8 20/40] x86/sev: Use SEV-SNP AP creation to start secondary CPUs Brijesh Singh
2021-12-10 18:50 ` Dave Hansen
2022-01-12 16:17 ` Brijesh Singh
2021-12-31 15:36 ` Borislav Petkov
2022-01-03 18:10 ` Vlastimil Babka
2022-01-12 16:33 ` Brijesh Singh [this message]
2022-01-12 17:10 ` Tom Lendacky
2022-01-13 12:23 ` Borislav Petkov
2022-01-13 12:21 ` Borislav Petkov
2021-12-10 15:43 ` [PATCH v8 21/40] x86/head: re-enable stack protection for 32/64-bit builds Brijesh Singh
2022-01-03 16:49 ` Borislav Petkov
2021-12-10 15:43 ` [PATCH v8 22/40] x86/sev: move MSR-based VMGEXITs for CPUID to helper Brijesh Singh
2021-12-30 18:52 ` Sean Christopherson
2022-01-04 20:57 ` Borislav Petkov
2022-01-04 23:36 ` Michael Roth
2022-01-06 18:38 ` Venu Busireddy
2022-01-06 20:21 ` Michael Roth
2022-01-06 20:36 ` Venu Busireddy
2021-12-10 15:43 ` [PATCH v8 23/40] KVM: x86: move lookup of indexed CPUID leafs " Brijesh Singh
2022-01-06 18:46 ` Venu Busireddy
2021-12-10 15:43 ` [PATCH v8 24/40] x86/compressed/acpi: move EFI system table lookup " Brijesh Singh
2021-12-10 18:54 ` Dave Hansen
2021-12-13 15:47 ` Michael Roth
2021-12-13 16:21 ` Dave Hansen
2021-12-13 18:00 ` Michael Roth
2022-01-11 8:59 ` Chao Fan
2022-01-05 23:50 ` Borislav Petkov
2022-01-06 19:59 ` Venu Busireddy
2021-12-10 15:43 ` [PATCH v8 25/40] x86/compressed/acpi: move EFI config " Brijesh Singh
2022-01-06 20:33 ` Venu Busireddy
2021-12-10 15:43 ` [PATCH v8 26/40] x86/compressed/acpi: move EFI vendor " Brijesh Singh
2022-01-06 20:47 ` Venu Busireddy
2021-12-10 15:43 ` [PATCH v8 27/40] x86/boot: Add Confidential Computing type to setup_data Brijesh Singh
2021-12-10 19:12 ` Dave Hansen
2021-12-10 20:18 ` Brijesh Singh
2021-12-10 20:30 ` Dave Hansen
2021-12-13 14:49 ` Brijesh Singh
2021-12-13 15:08 ` Dave Hansen
2021-12-13 15:55 ` Brijesh Singh
2022-01-07 11:54 ` Borislav Petkov
2022-01-06 22:48 ` Venu Busireddy
2021-12-10 15:43 ` [PATCH v8 28/40] KVM: SEV: Add documentation for SEV-SNP CPUID Enforcement Brijesh Singh
2022-01-07 13:22 ` Borislav Petkov
2021-12-10 15:43 ` [PATCH v8 29/40] x86/compressed/64: add support for SEV-SNP CPUID table in #VC handlers Brijesh Singh
2022-01-13 13:16 ` Borislav Petkov
2022-01-13 16:39 ` Michael Roth
2022-01-14 16:13 ` Borislav Petkov
2022-01-18 4:35 ` Michael Roth
2022-01-18 14:02 ` Borislav Petkov
2022-01-18 14:23 ` Michael Roth
2022-01-18 14:32 ` Michael Roth
2022-01-18 14:37 ` Michael Roth
2022-01-18 16:34 ` Borislav Petkov
2022-01-18 17:20 ` Michael Roth
2022-01-18 17:41 ` Borislav Petkov
2022-01-18 18:49 ` Michael Roth
2022-01-19 1:18 ` Michael Roth
2022-01-19 11:17 ` Borislav Petkov
2022-01-19 16:27 ` Michael Roth
2022-01-27 17:23 ` Michael Roth
2022-01-28 22:58 ` Borislav Petkov
2021-12-10 15:43 ` [PATCH v8 30/40] x86/boot: add a pointer to Confidential Computing blob in bootparams Brijesh Singh
2022-01-17 18:14 ` Borislav Petkov
2021-12-10 15:43 ` [PATCH v8 31/40] x86/compressed: add SEV-SNP feature detection/setup Brijesh Singh
2022-01-19 12:55 ` Borislav Petkov
2021-12-10 15:43 ` [PATCH v8 32/40] x86/compressed: use firmware-validated CPUID for SEV-SNP guests Brijesh Singh
2022-01-20 12:18 ` Borislav Petkov
2021-12-10 15:43 ` [PATCH v8 33/40] x86/compressed/64: add identity mapping for Confidential Computing blob Brijesh Singh
2021-12-10 19:52 ` Dave Hansen
2021-12-13 17:54 ` Michael Roth
2022-01-25 13:48 ` Borislav Petkov
2021-12-10 15:43 ` [PATCH v8 34/40] x86/sev: add SEV-SNP feature detection/setup Brijesh Singh
2022-01-25 18:43 ` Borislav Petkov
2021-12-10 15:43 ` [PATCH v8 35/40] x86/sev: use firmware-validated CPUID for SEV-SNP guests Brijesh Singh
2022-01-26 18:35 ` Borislav Petkov
2021-12-10 15:43 ` [PATCH v8 36/40] x86/sev: Provide support for SNP guest request NAEs Brijesh Singh
2022-01-27 16:21 ` Borislav Petkov
2022-01-27 17:02 ` Brijesh Singh
2022-01-29 10:27 ` Borislav Petkov
2022-01-29 11:49 ` Brijesh Singh
2022-01-29 12:02 ` Borislav Petkov
2021-12-10 15:43 ` [PATCH v8 37/40] x86/sev: Register SNP guest request platform device Brijesh Singh
2021-12-10 15:43 ` [PATCH v8 38/40] virt: Add SEV-SNP guest driver Brijesh Singh
2021-12-10 15:43 ` [PATCH v8 39/40] virt: sevguest: Add support to derive key Brijesh Singh
2021-12-10 22:27 ` Liam Merwick
2021-12-10 15:43 ` [PATCH v8 40/40] virt: sevguest: Add support to get extended report Brijesh Singh
2021-12-10 20:17 ` [PATCH v8 00/40] Add AMD Secure Nested Paging (SEV-SNP) Guest Support Dave Hansen
2021-12-10 20:20 ` Brijesh Singh
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