From: "Laszlo Ersek" <lersek@redhat.com>
To: devel@edk2.groups.io, brijesh.singh@amd.com
Cc: James Bottomley <jejb@linux.ibm.com>, Min Xu <min.m.xu@intel.com>,
Jiewen Yao <jiewen.yao@intel.com>,
Tom Lendacky <thomas.lendacky@amd.com>,
Jordan Justen <jordan.l.justen@intel.com>,
Ard Biesheuvel <ardb+tianocore@kernel.org>,
Erdem Aktas <erdemaktas@google.com>
Subject: Re: [edk2-devel] [PATCH RFC v2 04/28] MdePkg: Define the Page State Change VMGEXIT structures
Date: Tue, 4 May 2021 15:59:59 +0200 [thread overview]
Message-ID: <3782d6d7-bb52-5112-06f9-d05f8d404560@redhat.com> (raw)
In-Reply-To: <47d74104-dd86-8bb9-ba5e-6c0e7371d5e4@redhat.com>
On 05/04/21 14:33, Laszlo Ersek wrote:
> On 04/30/21 13:51, Brijesh Singh wrote:
>> BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=3275
>>
>> The Page State Change NAE exit will be used by the SEV-SNP guest to
>> request a page state change using the GHCB protocol. See the GHCB
>> spec section 4.1.6 and 2.3.1 for more detail on the structure
>> definitions.
>>
>> Cc: James Bottomley <jejb@linux.ibm.com>
>> Cc: Min Xu <min.m.xu@intel.com>
>> Cc: Jiewen Yao <jiewen.yao@intel.com>
>> Cc: Tom Lendacky <thomas.lendacky@amd.com>
>> Cc: Jordan Justen <jordan.l.justen@intel.com>
>> Cc: Ard Biesheuvel <ardb+tianocore@kernel.org>
>> Cc: Laszlo Ersek <lersek@redhat.com>
>> Cc: Erdem Aktas <erdemaktas@google.com>
>> Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
>> ---
>> MdePkg/Include/Register/Amd/Fam17Msr.h | 15 ++++++++++
>> MdePkg/Include/Register/Amd/Ghcb.h | 29 ++++++++++++++++++++
>> 2 files changed, 44 insertions(+)
>>
>> diff --git a/MdePkg/Include/Register/Amd/Fam17Msr.h b/MdePkg/Include/Register/Amd/Fam17Msr.h
>> index e19bd04b6c..432cee2feb 100644
>> --- a/MdePkg/Include/Register/Amd/Fam17Msr.h
>> +++ b/MdePkg/Include/Register/Amd/Fam17Msr.h
>> @@ -58,6 +58,19 @@ typedef union {
>> UINT64 GuestFrameNumber:52;
>> } GhcbGpaRegister;
>>
>> + struct {
>> + UINT64 Function:12;
>> + UINT64 GuestFrameNumber:40;
>> + UINT64 Operation:4;
>> + UINT64 Reserved:8;
>> + } SnpPageStateChangeRequest;
>> +
>> + struct {
>> + UINT32 Function:12;
>> + UINT32 Reserved:20;
>> + UINT32 ErrorCode;
>> + } SnpPageStateChangeResponse;
>> +
>> VOID *Ghcb;
>>
> This matches section 2.3.1 in rev 2.00.
>
>> UINT64 GhcbPhysicalAddress;
>> @@ -69,6 +82,8 @@ typedef union {
>> #define GHCB_INFO_CPUID_RESPONSE 5
>> #define GHCB_INFO_GHCB_GPA_REGISTER_REQUEST 18
>> #define GHCB_INFO_GHCB_GPA_REGISTER_RESPONSE 19
>> +#define GHCB_INFO_SNP_PAGE_STATE_CHANGE_REQUEST 20
>> +#define GHCB_INFO_SNP_PAGE_STATE_CHANGE_RESPONSE 21
>> #define GHCB_HYPERVISOR_FEATURES_REQUEST 128
>> #define GHCB_HYPERVISOR_FEATURES_RESPONSE 129
>> #define GHCB_INFO_TERMINATE_REQUEST 256
>
> Matches section 2.3.1.
>
>> diff --git a/MdePkg/Include/Register/Amd/Ghcb.h b/MdePkg/Include/Register/Amd/Ghcb.h
>> index 2d64a4c28f..1e7c0daed3 100644
>> --- a/MdePkg/Include/Register/Amd/Ghcb.h
>> +++ b/MdePkg/Include/Register/Amd/Ghcb.h
>> @@ -54,6 +54,7 @@
>> #define SVM_EXIT_NMI_COMPLETE 0x80000003ULL
>> #define SVM_EXIT_AP_RESET_HOLD 0x80000004ULL
>> #define SVM_EXIT_AP_JUMP_TABLE 0x80000005ULL
>> +#define SVM_EXIT_SNP_PAGE_STATE_CHANGE 0x80000010ULL
>> #define SVM_EXIT_HYPERVISOR_FEATURES 0x8000FFFDULL
>> #define SVM_EXIT_UNSUPPORTED 0x8000FFFFULL
>>
>
> Matches "Table 5. List of Supported Non-Automatic Events".
>
>> @@ -160,4 +161,32 @@ typedef union {
>> #define GHCB_HV_FEATURES_SNP_AP_CREATE (GHCB_HV_FEATURES_SNP | BIT1)
>> #define GHCB_HV_FEATURES_SNP_RESTRICTED_INJECTION (GHCB_HV_FEATURES_SNP_AP_CREATE | BIT2)
>> #define GHCB_HV_FEATURES_SNP_RESTRICTED_INJECTION_TIMER (GHCB_HV_FEATURES_SNP_RESTRICTED_INJECTION | BIT3)
>> +
>> +// SNP Page State Change
>
> (1) Comment style.
>
>> +#define SNP_PAGE_STATE_MAX_NPAGES 4095
>> +#define SNP_PAGE_STATE_MAX_ENTRY 253
>> +#define SNP_PAGE_STATE_PRIVATE 1
>> +#define SNP_PAGE_STATE_SHARED 2
>> +#define SNP_PAGE_STATE_PSMASH 3
>> +#define SNP_PAGE_STATE_UNSMASH 4
>
> (2) The PSMASH and UNSMASH operations are not documented in the rev 2.00
> spec, in the GHCB MSR protocol. That's probably because PSMASH and
> UNSMASH can only be defined in terms of 2MB pages, and
> GHCB_INFO_SNP_PAGE_STATE_CHANGE_REQUEST is suitable only for individual,
> 4KB pages. I think it would be useful to point out somehow here that
> PSMASH and UNSMASH are restricted to the GHCB shared area protocol
> (perhaps extend the leading comment on this block of macros).
>
> (3) I don't understand what "MAX_NPAGES" stands for (4095). The rest of
> the series never uses the macro, and I can't associate it with anything
> from the spec. If the macro is supposed to relate to the 4KB / 2MB page
> smashing / splitting, then its replacement text should be 512. Unless
> the macro corresponds to a definition in the spec, I think we should
> drop it.
>
>> +
>> +typedef PACKED struct {
>> + UINT64 CurrentPage:12;
>> + UINT64 GuestFrameNumber:40;
>> + UINT64 Op:4;
>> + UINT64 PageSize:1;
>> + UINT64 Rsvd: 7;
>> +} SNP_PAGE_STATE_ENTRY;
>> +
>> +typedef PACKED struct {
>> + UINT16 CurrentEntry;
>> + UINT16 EndEntry;
>> + UINT32 Rsvd;
>> +} SNP_PAGE_STATE_HEADER;
>
> (4) We tend to write
>
> #pragma pack (1)
> ...
> #pragma pack ()
>
> rather than PACKED -- but anyway, is packing really necessary? "Natural
> alignment" is required in edk2. I'm OK with packing, but I think the
> pragma is the preferred form.
>
> (5) Please spell out both "Rsvd" fields above as "Reserved".
>
> (6) Stray space character in "Rsvd: 7".
>
> (7) The field name "Op" is inconsistent with the other field name
> "Operation".
>
> (8) I think there is a bug (typo) in the rev 2.00 spec, in 4.1.6 "SNP
> Page State Change": it says
>
> ... calculated from the supplied guest physical frame number (GFN) for
> the requested page size (GPA = GFN << 12).
>
> But, if you can choose 2MB page size in the request, then the (GPA = GFN
> << 12) formula is not g
Sorry, unfinished sentence: I meant that the formula was not generally
correct.
Thanks
Laszlo
>
> (9) If my understanding of the spec is correct, "EndEntry" has
> *inclusive* meaning. That's unusual. Any particular reason for not
> making "EndEntry" exclusive (in the spec)?
>
>> +
>> +typedef struct {
>> + SNP_PAGE_STATE_HEADER Header;
>> + SNP_PAGE_STATE_ENTRY Entry[SNP_PAGE_STATE_MAX_ENTRY];
>> +} SNP_PAGE_STATE_CHANGE_INFO;
>> +
>> #endif
>>
>
> Yes, this looks OK. Size is 2+2+4+253*8 = 2032 bytes, which matches the
> size of GHCB.SharedBuffer.
>
> (10) However, *if* you decide to declare SNP_PAGE_STATE_ENTRY and
> SNP_PAGE_STATE_HEADER explicitly as packed, then you should do the same
> for SNP_PAGE_STATE_CHANGE_INFO.
>
> (11) Like I mentioned earlier, it's probably helpful if you start the
> subject line with
>
> MdePkg/Register/Amd: ...
>
> on all of these MdePkg patches. If that becomes too tight, for some of
> the MdePkg patches, then I suggest "MdePkg/Amd: ..." (i.e., drop
> "Register").
>
> Thanks
> Laszlo
>
next prev parent reply other threads:[~2021-05-04 14:00 UTC|newest]
Thread overview: 81+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-30 11:51 [PATCH RFC v2 00/28] Add AMD Secure Nested Paging (SEV-SNP) support Brijesh Singh
2021-04-30 11:51 ` [PATCH RFC v2 01/28] MdePkg: Expand the SEV MSR to include the SNP definition Brijesh Singh
2021-05-03 8:39 ` [edk2-devel] " Laszlo Ersek
2021-05-03 11:42 ` Brijesh Singh
2021-04-30 11:51 ` [PATCH RFC v2 02/28] MdePkg: Define the GHCB Hypervisor features Brijesh Singh
2021-05-03 10:10 ` [edk2-devel] " Laszlo Ersek
2021-05-03 12:20 ` Brijesh Singh
2021-05-03 13:40 ` Laszlo Ersek
2021-04-30 11:51 ` [PATCH RFC v2 03/28] MdePkg: Define the GHCB GPA structure Brijesh Singh
2021-05-03 10:24 ` [edk2-devel] " Laszlo Ersek
2021-05-03 12:19 ` Laszlo Ersek
2021-05-03 12:55 ` Brijesh Singh
2021-05-03 13:50 ` Laszlo Ersek
2021-05-03 13:55 ` Laszlo Ersek
2021-04-30 11:51 ` [PATCH RFC v2 04/28] MdePkg: Define the Page State Change VMGEXIT structures Brijesh Singh
2021-05-04 12:33 ` [edk2-devel] " Laszlo Ersek
2021-05-04 13:59 ` Laszlo Ersek [this message]
2021-05-04 14:48 ` Lendacky, Thomas
2021-05-04 18:07 ` Laszlo Ersek
2021-05-04 18:53 ` Brijesh Singh
2021-05-05 18:24 ` Laszlo Ersek
2021-05-05 19:27 ` Brijesh Singh
2021-04-30 11:51 ` [PATCH RFC v2 05/28] MdePkg: Add AsmPvalidate() support Brijesh Singh
2021-05-04 13:58 ` [edk2-devel] " Laszlo Ersek
2021-05-04 14:09 ` Laszlo Ersek
2021-05-04 19:07 ` Brijesh Singh
2021-05-05 18:56 ` Laszlo Ersek
[not found] ` <167BF2A01FA60569.6407@groups.io>
2021-05-04 19:55 ` Brijesh Singh
2021-05-05 19:10 ` Laszlo Ersek
[not found] ` <167BF53DA09B327E.22277@groups.io>
2021-05-04 20:28 ` Brijesh Singh
2021-05-04 23:03 ` Brijesh Singh
2021-05-05 19:19 ` Laszlo Ersek
2021-05-05 19:17 ` Laszlo Ersek
2021-04-30 11:51 ` [PATCH RFC v2 06/28] OvmfPkg/BaseMemEncryptSevLib: Introduce MemEncryptSevClearMmioPageEncMask() Brijesh Singh
2021-05-06 10:39 ` [edk2-devel] " Laszlo Ersek
2021-05-06 19:18 ` Brijesh Singh
2021-04-30 11:51 ` [PATCH RFC v2 07/28] OvmfPkg: Use MemEncryptSevClearMmioPageEncMask() to clear EncMask from Mmio Brijesh Singh
2021-05-06 10:50 ` [edk2-devel] " Laszlo Ersek
2021-05-06 19:20 ` Brijesh Singh
2021-04-30 11:51 ` [PATCH RFC v2 08/28] OvmfPkg/BaseMemEncryptSevLib: Remove CacheFlush parameter Brijesh Singh
2021-05-06 11:08 ` [edk2-devel] " Laszlo Ersek
2021-04-30 11:51 ` [PATCH RFC v2 09/28] OvmfPkg/VmgExitLib: Allow PMBASE register access in Dxe phase Brijesh Singh
2021-05-06 14:08 ` [edk2-devel] " Laszlo Ersek
2021-05-06 14:12 ` Laszlo Ersek
2021-05-07 13:29 ` Brijesh Singh
2021-05-07 15:10 ` Laszlo Ersek
2021-05-07 15:19 ` Brijesh Singh
2021-05-07 15:47 ` Laszlo Ersek
2021-04-30 11:51 ` [PATCH RFC v2 10/28] OvmfPkg/MemEncryptSevLib: add MemEncryptSevSnpEnabled() Brijesh Singh
2021-04-30 11:51 ` [PATCH RFC v2 11/28] OvmfPkg: Reserve Secrets page in MEMFD Brijesh Singh
2021-05-05 6:42 ` [edk2-devel] " Dov Murik
2021-05-05 13:11 ` Brijesh Singh
2021-05-05 19:33 ` Laszlo Ersek
2021-05-06 10:57 ` Dov Murik
2021-05-06 15:06 ` Laszlo Ersek
2021-05-06 16:12 ` James Bottomley
2021-05-06 16:02 ` James Bottomley
2021-04-30 11:51 ` [PATCH RFC v2 12/28] OvmfPkg: Reserve CPUID page for the SEV-SNP guest Brijesh Singh
2021-04-30 11:51 ` [PATCH RFC v2 13/28] OvmfPkg: Validate the data pages used in the Reset vector and SEC phase Brijesh Singh
2021-04-30 11:51 ` [PATCH RFC v2 14/28] UefiCpuPkg: Define the SEV-SNP specific dynamic PCDs Brijesh Singh
2021-04-30 11:51 ` [PATCH RFC v2 15/28] OvmfPkg/MemEncryptSevLib: extend the workarea to include SNP enabled field Brijesh Singh
2021-04-30 11:51 ` [PATCH RFC v2 16/28] OvmfPkg/MemEncryptSevLib: Extend Es Workarea to include hv features Brijesh Singh
2021-04-30 11:51 ` [PATCH RFC v2 17/28] OvmfPkg/ResetVector: Invalidate the GHCB page Brijesh Singh
2021-05-03 13:05 ` Erdem Aktas
2021-05-03 14:28 ` Brijesh Singh
2021-04-30 11:51 ` [PATCH RFC v2 18/28] OvmfPkg: Add a library to support registering GHCB GPA Brijesh Singh
2021-04-30 11:51 ` [PATCH RFC v2 19/28] OvmfPkg: register GHCB gpa for the SEV-SNP guest Brijesh Singh
2021-04-30 11:51 ` [PATCH RFC v2 20/28] UefiCpuPkg/MpLib: add support to register GHCB GPA when SEV-SNP is enabled Brijesh Singh
2021-04-30 11:51 ` [PATCH RFC v2 21/28] OvmfPkg/MemEncryptSevLib: Add support to validate system RAM Brijesh Singh
2021-05-03 14:04 ` Erdem Aktas
2021-05-03 18:56 ` Brijesh Singh
2021-04-30 11:51 ` [PATCH RFC v2 22/28] OvmfPkg/BaseMemEncryptSevLib: Skip the pre-validated " Brijesh Singh
2021-04-30 11:51 ` [PATCH RFC v2 23/28] OvmfPkg/MemEncryptSevLib: Add support to validate > 4GB memory in PEI phase Brijesh Singh
2021-04-30 11:51 ` [PATCH RFC v2 24/28] OvmfPkg/SecMain: Pre-validate the memory used for decompressing Fv Brijesh Singh
2021-04-30 11:51 ` [PATCH RFC v2 25/28] OvmfPkg/PlatformPei: Validate the system RAM when SNP is active Brijesh Singh
2021-04-30 11:51 ` [PATCH RFC v2 26/28] OvmfPkg/MemEncryptSevLib: Change the page state in the RMP table Brijesh Singh
2021-04-30 11:51 ` [PATCH RFC v2 27/28] OvmfPkg/AmdSev: Expose the SNP reserved pages through configuration table Brijesh Singh
2021-05-05 7:10 ` [edk2-devel] " Dov Murik
2021-05-05 19:37 ` Laszlo Ersek
2021-04-30 11:51 ` [PATCH RFC v2 28/28] MdePkg/GHCB: Increase the GHCB protocol max version Brijesh Singh
2021-04-30 16:49 ` [edk2-devel] [PATCH RFC v2 00/28] Add AMD Secure Nested Paging (SEV-SNP) support Laszlo Ersek
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