From: Michael Roth <michael.roth@amd.com>
To: Sean Christopherson <seanjc@google.com>
Cc: Brijesh Singh <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>,
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>,
Borislav Petkov <bp@alien8.de>,
"Vlastimil Babka" <vbabka@suse.cz>,
"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 22/40] x86/sev: move MSR-based VMGEXITs for CPUID to helper
Date: Tue, 4 Jan 2022 17:36:14 -0600 [thread overview]
Message-ID: <20220104233614.vnybv5sf54yiik7z@amd.com> (raw)
In-Reply-To: <Yc4ABL2EbBlwjma5@google.com>
On Thu, Dec 30, 2021 at 06:52:52PM +0000, Sean Christopherson wrote:
> On Fri, Dec 10, 2021, Brijesh Singh wrote:
> > From: Michael Roth <michael.roth@amd.com>
> >
> > This code will also be used later for SEV-SNP-validated CPUID code in
> > some cases, so move it to a common helper.
> >
> > Signed-off-by: Michael Roth <michael.roth@amd.com>
> > Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
> > ---
> > arch/x86/kernel/sev-shared.c | 84 +++++++++++++++++++++++++-----------
> > 1 file changed, 58 insertions(+), 26 deletions(-)
> >
> > diff --git a/arch/x86/kernel/sev-shared.c b/arch/x86/kernel/sev-shared.c
> > index 3aaef1a18ffe..d89481b31022 100644
> > --- a/arch/x86/kernel/sev-shared.c
> > +++ b/arch/x86/kernel/sev-shared.c
> > @@ -194,6 +194,58 @@ enum es_result sev_es_ghcb_hv_call(struct ghcb *ghcb, bool set_ghcb_msr,
> > return verify_exception_info(ghcb, ctxt);
> > }
> >
> > +static int sev_cpuid_hv(u32 func, u32 subfunc, u32 *eax, u32 *ebx,
>
> Having @subfunc, a.k.a. index, in is weird/confusing/fragile because it's not consumed,
> nor is it checked. Peeking ahead, it looks like all future users pass '0'. Taking the
> index but dropping it on the floor is asking for future breakage. Either drop it or
> assert that it's zero.
>
> > + u32 *ecx, u32 *edx)
> > +{
> > + u64 val;
> > +
> > + if (eax) {
> > + sev_es_wr_ghcb_msr(GHCB_CPUID_REQ(func, GHCB_CPUID_REQ_EAX));
> > + VMGEXIT();
> > + val = sev_es_rd_ghcb_msr();
> > +
> > + if (GHCB_RESP_CODE(val) != GHCB_MSR_CPUID_RESP)
> > + return -EIO;
> > +
> > + *eax = (val >> 32);
> > + }
> > +
> > + if (ebx) {
> > + sev_es_wr_ghcb_msr(GHCB_CPUID_REQ(func, GHCB_CPUID_REQ_EBX));
> > + VMGEXIT();
> > + val = sev_es_rd_ghcb_msr();
> > +
> > + if (GHCB_RESP_CODE(val) != GHCB_MSR_CPUID_RESP)
> > + return -EIO;
> > +
> > + *ebx = (val >> 32);
> > + }
> > +
> > + if (ecx) {
> > + sev_es_wr_ghcb_msr(GHCB_CPUID_REQ(func, GHCB_CPUID_REQ_ECX));
> > + VMGEXIT();
> > + val = sev_es_rd_ghcb_msr();
> > +
> > + if (GHCB_RESP_CODE(val) != GHCB_MSR_CPUID_RESP)
> > + return -EIO;
> > +
> > + *ecx = (val >> 32);
> > + }
> > +
> > + if (edx) {
> > + sev_es_wr_ghcb_msr(GHCB_CPUID_REQ(func, GHCB_CPUID_REQ_EDX));
> > + VMGEXIT();
> > + val = sev_es_rd_ghcb_msr();
> > +
> > + if (GHCB_RESP_CODE(val) != GHCB_MSR_CPUID_RESP)
> > + return -EIO;
> > +
> > + *edx = (val >> 32);
> > + }
>
> That's a lot of pasta! If you add
>
> static int __sev_cpuid_hv(u32 func, int reg_idx, u32 *reg)
> {
> u64 val;
>
> if (!reg)
> return 0;
>
> sev_es_wr_ghcb_msr(GHCB_CPUID_REQ(func, reg_idx));
> VMGEXIT();
> val = sev_es_rd_ghcb_msr();
> if (GHCB_RESP_CODE(val) != GHCB_MSR_CPUID_RESP)
> return -EIO;
>
> *reg = (val >> 32);
> return 0;
> }
>
> then this helper can become something like:
>
> static int sev_cpuid_hv(u32 func, u32 *eax, u32 *ebx, u32 *ecx, u32 *edx)
> {
> int ret;
>
> ret = __sev_cpuid_hv(func, GHCB_CPUID_REQ_EAX, eax);
> ret = ret ? : __sev_cpuid_hv(func, GHCB_CPUID_REQ_EBX, ebx);
> ret = ret ? : __sev_cpuid_hv(func, GHCB_CPUID_REQ_ECX, ecx);
> ret = ret ? : __sev_cpuid_hv(func, GHCB_CPUID_REQ_EDX, edx);
>
> return ret;
Looks good, will make these changes.
-Mike
next prev parent reply other threads:[~2022-01-04 23:42 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
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 [this message]
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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