[PATCH v3 16/19] x86/sev: Avoid WARN() in early code

Ard Biesheuvel
2024-01-29T18:06:08Z

From: Ard Biesheuvel <ardb@kernel.org>

Drop uses of WARN() from code that is reachable from the early primary
boot path which executes via the initial 1:1 mapping before the kernel
page tables are populated. This is unsafe and mostly pointless, given
that printk() does not actually work yet at this point.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
---
arch/x86/kernel/sev.c | 13 ++++---------
1 file changed, 4 insertions(+), 9 deletions(-)

diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c
index 62981b463b76..94bf054bbde3 100644
--- a/arch/x86/kernel/sev.c
+++ b/arch/x86/kernel/sev.c
@@ -698,7 +698,7 @@ static void __pitext early_set_pages_state(unsigned long vaddr, unsigned long pa
if (op == SNP_PAGE_STATE_SHARED) {
/* Page validation must be rescinded before changing to shared */
ret = pvalidate(vaddr, RMP_PG_SIZE_4K, false);
- if (WARN(ret, "Failed to validate address 0x%lx ret %d", paddr, ret))
+ if (ret)
goto e_term;
}

@@ -711,21 +711,16 @@ static void __pitext early_set_pages_state(unsigned long vaddr, unsigned long pa

val = sev_es_rd_ghcb_msr();

- if (WARN(GHCB_RESP_CODE(val) != GHCB_MSR_PSC_RESP,
- "Wrong PSC response code: 0x%x\n",
- (unsigned int)GHCB_RESP_CODE(val)))
+ if (GHCB_RESP_CODE(val) != GHCB_MSR_PSC_RESP)
goto e_term;

- if (WARN(GHCB_MSR_PSC_RESP_VAL(val),
- "Failed to change page state to '%s' paddr 0x%lx error 0x%llx\n",
- op == SNP_PAGE_STATE_PRIVATE ? "private" : "shared",
- paddr, GHCB_MSR_PSC_RESP_VAL(val)))
+ if (GHCB_MSR_PSC_RESP_VAL(val))
goto e_term;

if (op == SNP_PAGE_STATE_PRIVATE) {
/* Page validation must be performed after changing to private */
ret = pvalidate(vaddr, RMP_PG_SIZE_4K, true);
- if (WARN(ret, "Failed to validate address 0x%lx ret %d", paddr, ret))
+ if (ret)
goto e_term;
}

--
2.43.0.429.g432eaa2c6b-goog