From: Brijesh Singh <brijesh.singh@amd.com>
To: Borislav Petkov <bp@alien8.de>
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,
linux-crypto@vger.kernel.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>,
Wanpeng Li <wanpengli@tencent.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>,
Vlastimil Babka <vbabka@suse.cz>,
tony.luck@intel.com, npmccallum@redhat.com,
brijesh.ksingh@gmail.com
Subject: Re: [PATCH Part1 RFC v4 15/36] x86/mm: Add support to validate memory when changing C-bit
Date: Tue, 17 Aug 2021 13:07:40 -0500 [thread overview]
Message-ID: <162d75ca-f0ec-bb7e-bb47-70060772a52c@amd.com> (raw)
In-Reply-To: <YRvxZtLkVNda9xwX@zn.tnic>
On 8/17/21 12:27 PM, Borislav Petkov wrote:
>
> The majority of kernel code puts __packed after the struct definition,
> let's put it there too pls, out of the way.
>
> ...
Noted.
>> + if (WARN(ret || ghcb->save.sw_exit_info_2,
>> + "SEV-SNP: page state change failed ret=%d exit_info_2=%llx\n",
>> + ret, ghcb->save.sw_exit_info_2))
>> + return 1;
>
> Yikes, you return here and below with interrupts disabled.
>
> All your returns need to be "goto out;" instead where you do
>
> out:
> __sev_put_ghcb(&state);
> local_irq_restore(flags);
>
> Yap, you very likely need to put the GHCB too.
>
Sure, let me revisit this code to fix those path.
>> + /*
>> + * Lets do some sanity check that entry processing is not going
>> + * backward. This will happen only if hypervisor is tricking us.
>> + */
>> + if (WARN((hdr->end_entry > end_entry) || (cur_entry > hdr->cur_entry),
>> + "SEV-SNP: page state change processing going backward, end_entry "
>> + "(expected %d got %d) cur_entry (expected %d got %d)\n",
>> + end_entry, hdr->end_entry, cur_entry, hdr->cur_entry))
>> + return 1;
>
> WARNING: quoted string split across lines
> #293: FILE: arch/x86/kernel/sev.c:750:
> + "SEV-SNP: page state change processing going backward, end_entry "
> + "(expected %d got %d) cur_entry (expected %d got %d)\n",
>
> If you're wondering what to do, yes, you can really stretch that string
> and shorten it too:
Okay.
>
> if (WARN((hdr->end_entry > end_entry) || (cur_entry > hdr->cur_entry),
> "SEV-SNP: PSC processing going backwards, end_entry %d (got %d) cur_entry: %d (got %d)\n",
> end_entry, hdr->end_entry, cur_entry, hdr->cur_entry))
> return 1;
>
> so that it fits on a single line and grepping can find it.
>
Noted.
>> + /* Lets verify that reserved bit is not set in the header*/
>> + if (WARN(hdr->reserved, "Reserved bit is set in the PSC header\n"))
>
> psc_entry has a ->reserved field too and since we're iterating over the
> entries...
>
Sure I can add that check.
>> +
>> + desc = kmalloc(sizeof(*desc), GFP_KERNEL_ACCOUNT);
>
> kzalloc() so that you don't have to memset() later in
> __set_page_state().
Depending on the size, the __set_page_state() can be call multiple times
so it should clear the desc memory before filling it.
>
>> + if (!desc)
>> + panic("failed to allocate memory");
>
> Make that error message more distinctive so that *if* it happens, one
> can pinpoint the place in the code where the panic comes from.
>
Now I am running checkpatch and notice that it complain about the
message too. I can add a BUG() or WARN() to get the stack trace before
the crashing.
>> + while (vaddr < vaddr_end) {
>> + /*
>> + * Calculate the last vaddr that can be fit in one
>> + * struct snp_psc_desc.
>> + */
>> + next_vaddr = min_t(unsigned long, vaddr_end,
>> + (VMGEXIT_PSC_MAX_ENTRY * PAGE_SIZE) + vaddr);
>> +
>> + __set_page_state(desc, vaddr, next_vaddr, op);
>> +
>> + vaddr = next_vaddr;
>> + }
>> +
>> + kfree(desc);
>> +}
>> +
>
next prev parent reply other threads:[~2021-08-17 18:07 UTC|newest]
Thread overview: 86+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-07 18:14 [PATCH Part1 RFC v4 00/36] Add AMD Secure Nested Paging (SEV-SNP) Guest Support Brijesh Singh
2021-07-07 18:14 ` [PATCH Part1 RFC v4 01/36] x86/sev: shorten GHCB terminate macro names Brijesh Singh
2021-07-07 18:14 ` [PATCH Part1 RFC v4 02/36] x86/sev: Save the negotiated GHCB version Brijesh Singh
2021-08-10 9:17 ` Borislav Petkov
2021-08-10 13:15 ` Brijesh Singh
2021-08-10 10:01 ` Borislav Petkov
2021-08-10 13:17 ` Brijesh Singh
2021-07-07 18:14 ` [PATCH Part1 RFC v4 03/36] x86/sev: Add support for hypervisor feature VMGEXIT Brijesh Singh
2021-08-10 11:22 ` Borislav Petkov
2021-08-10 13:39 ` Brijesh Singh
2021-08-10 14:03 ` Borislav Petkov
2021-07-07 18:14 ` [PATCH Part1 RFC v4 04/36] x86/mm: Add sev_feature_enabled() helper Brijesh Singh
2021-07-08 8:50 ` Dr. David Alan Gilbert
2021-07-08 8:53 ` Paolo Bonzini
2021-08-10 11:25 ` Borislav Petkov
2021-08-10 14:57 ` Brijesh Singh
2021-07-07 18:14 ` [PATCH Part1 RFC v4 05/36] x86/sev: Define the Linux specific guest termination reasons Brijesh Singh
2021-08-10 11:33 ` Borislav Petkov
2021-08-10 14:59 ` Brijesh Singh
2021-08-10 19:30 ` Tom Lendacky
2021-08-10 21:52 ` Borislav Petkov
2021-07-07 18:14 ` [PATCH Part1 RFC v4 06/36] x86/sev: check SEV-SNP features support Brijesh Singh
2021-07-07 18:14 ` [PATCH Part1 RFC v4 07/36] x86/sev: Add a helper for the PVALIDATE instruction Brijesh Singh
2021-07-07 18:14 ` [PATCH Part1 RFC v4 08/36] x86/sev: check the vmpl level Brijesh Singh
2021-08-13 7:25 ` Borislav Petkov
2021-08-13 13:13 ` Brijesh Singh
2021-08-13 15:16 ` Borislav Petkov
2021-07-07 18:14 ` [PATCH Part1 RFC v4 09/36] x86/compressed: Add helper for validating pages in the decompression stage Brijesh Singh
2021-08-13 10:22 ` Borislav Petkov
2021-08-13 14:21 ` Brijesh Singh
2021-08-13 15:19 ` Borislav Petkov
2021-07-07 18:14 ` [PATCH Part1 RFC v4 10/36] x86/compressed: Register GHCB memory when SEV-SNP is active Brijesh Singh
2021-08-13 10:47 ` Borislav Petkov
2021-07-07 18:14 ` [PATCH Part1 RFC v4 11/36] x86/sev: " Brijesh Singh
2021-07-07 18:14 ` [PATCH Part1 RFC v4 12/36] x86/sev: Add helper for validating pages in early enc attribute changes Brijesh Singh
2021-08-13 11:13 ` Borislav Petkov
2021-07-07 18:14 ` [PATCH Part1 RFC v4 13/36] x86/kernel: Make the bss.decrypted section shared in RMP table Brijesh Singh
2021-08-13 17:09 ` Borislav Petkov
2021-07-07 18:14 ` [PATCH Part1 RFC v4 14/36] x86/kernel: Validate rom memory before accessing when SEV-SNP is active Brijesh Singh
2021-07-07 18:14 ` [PATCH Part1 RFC v4 15/36] x86/mm: Add support to validate memory when changing C-bit Brijesh Singh
2021-08-17 17:27 ` Borislav Petkov
2021-08-17 18:07 ` Brijesh Singh [this message]
2021-08-17 18:17 ` Borislav Petkov
2021-08-17 18:18 ` Brijesh Singh
2021-08-17 20:34 ` Brijesh Singh
2021-08-17 20:44 ` Borislav Petkov
2021-07-07 18:14 ` [PATCH Part1 RFC v4 16/36] KVM: SVM: define new SEV_FEATURES field in the VMCB Save State Area Brijesh Singh
2021-08-17 17:54 ` Borislav Petkov
2021-08-17 17:59 ` Borislav Petkov
2021-08-17 18:11 ` Brijesh Singh
2021-07-07 18:14 ` [PATCH Part1 RFC v4 17/36] KVM: SVM: Create a separate mapping for the SEV-ES save area Brijesh Singh
2021-07-07 18:14 ` [PATCH Part1 RFC v4 18/36] KVM: SVM: Create a separate mapping for the GHCB " Brijesh Singh
2021-07-07 18:14 ` [PATCH Part1 RFC v4 19/36] KVM: SVM: Update the SEV-ES save area mapping Brijesh Singh
2021-07-07 18:14 ` [PATCH Part1 RFC v4 20/36] x86/sev: Use SEV-SNP AP creation to start secondary CPUs Brijesh Singh
2021-08-17 20:04 ` Borislav Petkov
2021-08-17 22:13 ` Tom Lendacky
2021-08-18 8:38 ` Borislav Petkov
2021-07-07 18:14 ` [PATCH Part1 RFC v4 21/36] x86/head/64: set up a startup %gs for stack protector Brijesh Singh
2021-08-19 9:34 ` Borislav Petkov
2021-07-07 18:14 ` [PATCH Part1 RFC v4 22/36] x86/sev: move MSR-based VMGEXITs for CPUID to helper Brijesh Singh
2021-08-19 9:45 ` Borislav Petkov
2021-08-19 15:37 ` Michael Roth
2021-08-19 16:46 ` Borislav Petkov
2021-08-20 3:29 ` Michael Roth
2021-08-23 4:50 ` Borislav Petkov
2021-07-07 18:14 ` [PATCH Part1 RFC v4 23/36] KVM: x86: move lookup of indexed CPUID leafs " Brijesh Singh
2021-08-19 10:07 ` Borislav Petkov
2021-07-07 18:14 ` [PATCH Part1 RFC v4 24/36] x86/compressed/acpi: move EFI config table access to common code Brijesh Singh
2021-08-19 10:47 ` Borislav Petkov
2021-08-19 14:58 ` Michael Roth
2021-08-19 17:09 ` Borislav Petkov
2021-08-19 23:42 ` Michael Roth
2021-08-23 4:52 ` Borislav Petkov
2021-07-07 18:14 ` [PATCH Part1 RFC v4 25/36] x86/boot: Add Confidential Computing type to setup_data Brijesh Singh
2021-08-19 11:06 ` Borislav Petkov
2021-07-07 18:14 ` [PATCH Part1 RFC v4 26/36] x86/compressed/64: enable SEV-SNP-validated CPUID in #VC handler Brijesh Singh
2021-07-07 18:14 ` [PATCH Part1 RFC v4 27/36] x86/boot: add a pointer to Confidential Computing blob in bootparams Brijesh Singh
2021-07-07 18:14 ` [PATCH Part1 RFC v4 28/36] x86/compressed/64: store Confidential Computing blob address " Brijesh Singh
2021-07-07 18:14 ` [PATCH Part1 RFC v4 29/36] x86/compressed/64: add identity mapping for Confidential Computing blob Brijesh Singh
2021-07-07 18:15 ` [PATCH Part1 RFC v4 30/36] x86/sev: enable SEV-SNP-validated CPUID in #VC handlers Brijesh Singh
2021-07-07 18:15 ` [PATCH Part1 RFC v4 31/36] x86/sev: Provide support for SNP guest request NAEs Brijesh Singh
2021-07-07 18:15 ` [PATCH Part1 RFC v4 32/36] x86/sev: Add snp_msg_seqno() helper Brijesh Singh
2021-07-07 18:15 ` [PATCH Part1 RFC v4 33/36] x86/sev: Register SNP guest request platform device Brijesh Singh
2021-07-07 18:15 ` [PATCH Part1 RFC v4 34/36] virt: Add SEV-SNP guest driver Brijesh Singh
2021-07-07 18:15 ` [PATCH Part1 RFC v4 35/36] virt: sevguest: Add support to derive key Brijesh Singh
2021-07-07 18:15 ` [PATCH Part1 RFC v4 36/36] virt: sevguest: Add support to get extended report Brijesh Singh
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