linux-kernel - [tip: x86/urgent] x86/sev: Ensure SVSM reserved fields in a page validation entry are initialized to zero

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Message-ID: <175524871566.1420.6970992850866287220.tip-bot2@tip-bot2>
Date: Fri, 15 Aug 2025 09:05:15 -0000
From: "tip-bot2 for Tom Lendacky" <tip-bot2@...utronix.de>
To: linux-tip-commits@...r.kernel.org
Cc: Tom Lendacky <thomas.lendacky@....com>,
 "Borislav Petkov (AMD)" <bp@...en8.de>, Joerg Roedel <joerg.roedel@....com>,
 x86@...nel.org, linux-kernel@...r.kernel.org
Subject: [tip: x86/urgent] x86/sev: Ensure SVSM reserved fields in a page
 validation entry are initialized to zero

The following commit has been merged into the x86/urgent branch of tip:

Commit-ID:     d3be079da81f08d8d7f3416119b03e173d4285d2
Gitweb:        https://git.kernel.org/tip/d3be079da81f08d8d7f3416119b03e173d4285d2
Author:        Tom Lendacky <thomas.lendacky@....com>
AuthorDate:    Wed, 13 Aug 2025 10:26:59 -05:00
Committer:     Borislav Petkov (AMD) <bp@...en8.de>
CommitterDate: Fri, 15 Aug 2025 10:50:01 +02:00

x86/sev: Ensure SVSM reserved fields in a page validation entry are initialized to zero

In order to support future versions of the SVSM_CORE_PVALIDATE call, all
reserved fields within a PVALIDATE entry must be set to zero as an SVSM should
be ensuring all reserved fields are zero in order to support future usage of
reserved areas based on the protocol version.

Fixes: fcd042e86422 ("x86/sev: Perform PVALIDATE using the SVSM when not at VMPL0")
Signed-off-by: Tom Lendacky <thomas.lendacky@....com>
Signed-off-by: Borislav Petkov (AMD) <bp@...en8.de>
Reviewed-by: Joerg Roedel <joerg.roedel@....com>
Link: https://lore.kernel.org/7cde412f8b057ea13a646fb166b1ca023f6a5031.1755098819.git.thomas.lendacky@amd.com
---
 arch/x86/boot/startup/sev-shared.c | 1 +
 arch/x86/coco/sev/core.c           | 2 ++
 2 files changed, 3 insertions(+)

diff --git a/arch/x86/boot/startup/sev-shared.c b/arch/x86/boot/startup/sev-shared.c
index 7a706db..4ab0dbd 100644
--- a/arch/x86/boot/startup/sev-shared.c
+++ b/arch/x86/boot/startup/sev-shared.c
@@ -785,6 +785,7 @@ static void __head svsm_pval_4k_page(unsigned long paddr, bool validate)
 	pc->entry[0].page_size = RMP_PG_SIZE_4K;
 	pc->entry[0].action    = validate;
 	pc->entry[0].ignore_cf = 0;
+	pc->entry[0].rsvd      = 0;
 	pc->entry[0].pfn       = paddr >> PAGE_SHIFT;
 
 	/* Protocol 0, Call ID 1 */
diff --git a/arch/x86/coco/sev/core.c b/arch/x86/coco/sev/core.c
index fc59ce7..43ecc6b 100644
--- a/arch/x86/coco/sev/core.c
+++ b/arch/x86/coco/sev/core.c
@@ -227,6 +227,7 @@ static u64 svsm_build_ca_from_pfn_range(u64 pfn, u64 pfn_end, bool action,
 		pe->page_size = RMP_PG_SIZE_4K;
 		pe->action    = action;
 		pe->ignore_cf = 0;
+		pe->rsvd      = 0;
 		pe->pfn       = pfn;
 
 		pe++;
@@ -257,6 +258,7 @@ static int svsm_build_ca_from_psc_desc(struct snp_psc_desc *desc, unsigned int d
 		pe->page_size = e->pagesize ? RMP_PG_SIZE_2M : RMP_PG_SIZE_4K;
 		pe->action    = e->operation == SNP_PAGE_STATE_PRIVATE;
 		pe->ignore_cf = 0;
+		pe->rsvd      = 0;
 		pe->pfn       = e->gfn;
 
 		pe++;