From: Borislav Petkov <bp@alien8.de>
To: Brijesh Singh <brijesh.singh@amd.com>
Cc: x86@kernel.org, linux-kernel@vger.kernel.org,
kvm@vger.kernel.org, tglx@linutronix.de, jroedel@suse.de,
thomas.lendacky@amd.com, pbonzini@redhat.com, mingo@redhat.com,
dave.hansen@intel.com, rientjes@google.com, seanjc@google.com,
peterz@infradead.org, hpa@zytor.com, tony.luck@intel.com
Subject: Re: [PATCH Part1 RFC v2 02/20] x86/sev: Save the negotiated GHCB version
Date: Tue, 11 May 2021 11:23:05 +0200 [thread overview]
Message-ID: <YJpM+VZaEr68hTwZ@zn.tnic> (raw)
In-Reply-To: <20210430121616.2295-3-brijesh.singh@amd.com>
On Fri, Apr 30, 2021 at 07:15:58AM -0500, Brijesh Singh wrote:
> The SEV-ES guest calls the sev_es_negotiate_protocol() to negotiate the
> GHCB protocol version before establishing the GHCB. Cache the negotiated
> GHCB version so that it can be used later.
>
> Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
> ---
> arch/x86/include/asm/sev.h | 2 +-
> arch/x86/kernel/sev-shared.c | 15 ++++++++++++---
> 2 files changed, 13 insertions(+), 4 deletions(-)
>
> diff --git a/arch/x86/include/asm/sev.h b/arch/x86/include/asm/sev.h
> index fa5cd05d3b5b..7ec91b1359df 100644
> --- a/arch/x86/include/asm/sev.h
> +++ b/arch/x86/include/asm/sev.h
> @@ -12,7 +12,7 @@
> #include <asm/insn.h>
> #include <asm/sev-common.h>
>
> -#define GHCB_PROTO_OUR 0x0001UL
> +#define GHCB_PROTOCOL_MIN 1ULL
> #define GHCB_PROTOCOL_MAX 1ULL
> #define GHCB_DEFAULT_USAGE 0ULL
>
> diff --git a/arch/x86/kernel/sev-shared.c b/arch/x86/kernel/sev-shared.c
> index 6ec8b3bfd76e..48a47540b85f 100644
> --- a/arch/x86/kernel/sev-shared.c
> +++ b/arch/x86/kernel/sev-shared.c
> @@ -14,6 +14,13 @@
> #define has_cpuflag(f) boot_cpu_has(f)
> #endif
>
> +/*
> + * Since feature negotitation related variables are set early in the boot
> + * process they must reside in the .data section so as not to be zeroed
> + * out when the .bss section is later cleared.
*
* GHCB protocol version negotiated with the hypervisor.
*/
> +static u16 ghcb_version __section(".data") = 0;
Did you not see this when running checkpatch.pl on your patch?
ERROR: do not initialise statics to 0
#141: FILE: arch/x86/kernel/sev-shared.c:22:
+static u16 ghcb_version __section(".data") = 0;
> static bool __init sev_es_check_cpu_features(void)
> {
> if (!has_cpuflag(X86_FEATURE_RDRAND)) {
> @@ -54,10 +61,12 @@ static bool sev_es_negotiate_protocol(void)
> if (GHCB_MSR_INFO(val) != GHCB_MSR_SEV_INFO_RESP)
> return false;
>
> - if (GHCB_MSR_PROTO_MAX(val) < GHCB_PROTO_OUR ||
> - GHCB_MSR_PROTO_MIN(val) > GHCB_PROTO_OUR)
> + if (GHCB_MSR_PROTO_MAX(val) < GHCB_PROTOCOL_MIN ||
> + GHCB_MSR_PROTO_MIN(val) > GHCB_PROTOCOL_MAX)
> return false;
>
> + ghcb_version = min_t(size_t, GHCB_MSR_PROTO_MAX(val), GHCB_PROTOCOL_MAX);
How is that even supposed to work? GHCB_PROTOCOL_MAX is 1 so
ghcb_version will be always 1 when you do min_t() on values one of which
is 1.
Maybe I'm missing something...
--
Regards/Gruss,
Boris.
https://people.kernel.org/tglx/notes-about-netiquette
next prev parent reply other threads:[~2021-05-11 9:23 UTC|newest]
Thread overview: 62+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-30 12:15 [PATCH Part1 RFC v2 00/20] Add AMD Secure Nested Paging (SEV-SNP) Guest Support Brijesh Singh
2021-04-30 12:15 ` [PATCH Part1 RFC v2 01/20] x86/sev: Define the GHCB MSR protocol for AP reset hold Brijesh Singh
2021-04-30 12:15 ` [PATCH Part1 RFC v2 02/20] x86/sev: Save the negotiated GHCB version Brijesh Singh
2021-05-11 9:23 ` Borislav Petkov [this message]
2021-05-11 18:29 ` Brijesh Singh
2021-05-11 18:41 ` Borislav Petkov
2021-05-12 14:03 ` Brijesh Singh
2021-05-12 14:31 ` Borislav Petkov
2021-05-12 15:03 ` Brijesh Singh
2021-04-30 12:15 ` [PATCH Part1 RFC v2 03/20] x86/sev: Add support for hypervisor feature VMGEXIT Brijesh Singh
2021-05-11 10:01 ` Borislav Petkov
2021-05-11 18:53 ` Brijesh Singh
2021-05-17 14:40 ` Borislav Petkov
2021-04-30 12:16 ` [PATCH Part1 RFC v2 04/20] x86/sev: Increase the GHCB protocol version Brijesh Singh
2021-04-30 12:16 ` [PATCH Part1 RFC v2 05/20] x86/sev: Define SNP Page State Change VMGEXIT structure Brijesh Singh
2021-05-18 10:41 ` Borislav Petkov
2021-05-18 15:06 ` Brijesh Singh
2021-04-30 12:16 ` [PATCH Part1 RFC v2 06/20] x86/sev: Define SNP guest request NAE events Brijesh Singh
2021-05-18 10:45 ` Borislav Petkov
2021-05-18 13:42 ` Brijesh Singh
2021-05-18 13:54 ` Borislav Petkov
2021-05-18 14:13 ` Brijesh Singh
2021-04-30 12:16 ` [PATCH Part1 RFC v2 07/20] x86/sev: Define error codes for reason set 1 Brijesh Singh
2021-05-18 11:05 ` Borislav Petkov
2021-04-30 12:16 ` [PATCH Part1 RFC v2 08/20] x86/mm: Add sev_snp_active() helper Brijesh Singh
2021-05-18 18:11 ` Borislav Petkov
2021-05-19 17:28 ` Brijesh Singh
2021-04-30 12:16 ` [PATCH Part1 RFC v2 09/20] x86/sev: check SEV-SNP features support Brijesh Singh
2021-05-20 16:02 ` Borislav Petkov
2021-05-20 17:40 ` Brijesh Singh
2021-04-30 12:16 ` [PATCH Part1 RFC v2 10/20] x86/sev: Add a helper for the PVALIDATE instruction Brijesh Singh
2021-04-30 13:05 ` Brijesh Singh
2021-05-20 17:32 ` Borislav Petkov
2021-05-20 17:44 ` Brijesh Singh
2021-05-20 17:51 ` Borislav Petkov
2021-05-20 17:57 ` Brijesh Singh
2021-04-30 12:16 ` [PATCH Part1 RFC v2 11/20] x86/compressed: Add helper for validating pages in the decompression stage Brijesh Singh
2021-05-20 17:52 ` Borislav Petkov
2021-05-20 18:05 ` Brijesh Singh
2021-05-25 10:18 ` Borislav Petkov
2021-04-30 12:16 ` [PATCH Part1 RFC v2 12/20] x86/compressed: Register GHCB memory when SEV-SNP is active Brijesh Singh
2021-05-25 10:41 ` Borislav Petkov
2021-04-30 12:16 ` [PATCH Part1 RFC v2 13/20] x86/sev: " Brijesh Singh
2021-05-25 11:11 ` Borislav Petkov
2021-05-25 14:28 ` Brijesh Singh
2021-05-25 14:35 ` Borislav Petkov
2021-05-25 14:47 ` Brijesh Singh
2021-05-26 9:57 ` Borislav Petkov
2021-05-26 13:23 ` Brijesh Singh
2021-04-30 12:16 ` [PATCH Part1 RFC v2 14/20] x86/sev: Add helper for validating pages in early enc attribute changes Brijesh Singh
2021-05-26 10:39 ` Borislav Petkov
2021-05-26 13:34 ` Brijesh Singh
2021-04-30 12:16 ` [PATCH Part1 RFC v2 15/20] x86/kernel: Make the bss.decrypted section shared in RMP table Brijesh Singh
2021-04-30 12:16 ` [PATCH Part1 RFC v2 16/20] x86/kernel: Validate rom memory before accessing when SEV-SNP is active Brijesh Singh
2021-05-27 11:49 ` Borislav Petkov
2021-05-27 12:12 ` Brijesh Singh
2021-05-27 12:23 ` Borislav Petkov
2021-05-27 12:56 ` Brijesh Singh
2021-04-30 12:16 ` [PATCH Part1 RFC v2 17/20] x86/mm: Add support to validate memory when changing C-bit Brijesh Singh
2021-04-30 12:16 ` [PATCH Part1 RFC v2 18/20] x86/boot: Add Confidential Computing address to setup_header Brijesh Singh
2021-04-30 12:16 ` [PATCH Part1 RFC v2 19/20] x86/sev: Register SNP guest request platform device Brijesh Singh
2021-04-30 12:16 ` [PATCH Part1 RFC v2 20/20] virt: Add SEV-SNP guest driver Brijesh Singh
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