linux-kernel - Re: [PATCH v1 07/26] x86/fault: Add helper for dumping RMP entries

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Date: Wed, 10 Jan 2024 10:59:12 +0100
From: Borislav Petkov <bp@...en8.de>
To: Michael Roth <michael.roth@....com>
Cc: x86@...nel.org, kvm@...r.kernel.org, linux-coco@...ts.linux.dev,
	linux-mm@...ck.org, linux-crypto@...r.kernel.org,
	linux-kernel@...r.kernel.org, tglx@...utronix.de, mingo@...hat.com,
	jroedel@...e.de, thomas.lendacky@....com, hpa@...or.com,
	ardb@...nel.org, pbonzini@...hat.com, seanjc@...gle.com,
	vkuznets@...hat.com, jmattson@...gle.com, luto@...nel.org,
	dave.hansen@...ux.intel.com, slp@...hat.com, pgonda@...gle.com,
	peterz@...radead.org, srinivas.pandruvada@...ux.intel.com,
	rientjes@...gle.com, tobin@....com, vbabka@...e.cz,
	kirill@...temov.name, ak@...ux.intel.com, tony.luck@...el.com,
	sathyanarayanan.kuppuswamy@...ux.intel.com, alpergun@...gle.com,
	jarkko@...nel.org, ashish.kalra@....com, nikunj.dadhania@....com,
	pankaj.gupta@....com, liam.merwick@...cle.com, zhi.a.wang@...el.com,
	Brijesh Singh <brijesh.singh@....com>
Subject: Re: [PATCH v1 07/26] x86/fault: Add helper for dumping RMP entries

On Sat, Dec 30, 2023 at 10:19:35AM -0600, Michael Roth wrote:
> +void snp_dump_hva_rmpentry(unsigned long hva)
> +{
> +	unsigned int level;
> +	pgd_t *pgd;
> +	pte_t *pte;
> +
> +	pgd = __va(read_cr3_pa());
> +	pgd += pgd_index(hva);
> +	pte = lookup_address_in_pgd(pgd, hva, &level);
> +
> +	if (!pte) {
> +		pr_info("Can't dump RMP entry for HVA %lx: no PTE/PFN found\n", hva);
> +		return;
> +	}
> +
> +	dump_rmpentry(pte_pfn(*pte));
> +}
> +EXPORT_SYMBOL_GPL(snp_dump_hva_rmpentry);

show_fault_oops() - the only caller of this - is builtin code and thus
doesn't need symbol exports. Symbol exports are only for module code.

---
diff --git a/arch/x86/virt/svm/sev.c b/arch/x86/virt/svm/sev.c
index a8cf33b7da71..31154f087fb0 100644
--- a/arch/x86/virt/svm/sev.c
+++ b/arch/x86/virt/svm/sev.c
@@ -339,4 +339,3 @@ void snp_dump_hva_rmpentry(unsigned long hva)
 
 	dump_rmpentry(pte_pfn(*pte));
 }
-EXPORT_SYMBOL_GPL(snp_dump_hva_rmpentry);

-- 
Regards/Gruss,
    Boris.

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