linux-kernel - Re: [PATCH v2 16/25] crypto: ccp: Handle the legacy TMR allocation when SNP is enabled

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Date: Mon, 29 Jan 2024 16:04:28 +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,
	Brijesh Singh <brijesh.singh@....com>
Subject: Re: [PATCH v2 16/25] crypto: ccp: Handle the legacy TMR allocation
 when SNP is enabled

On Thu, Jan 25, 2024 at 10:11:16PM -0600, Michael Roth wrote:
> @@ -641,14 +774,16 @@ static int __sev_platform_init_locked(int *error)

That function - especially when looking at the next patch - becomes too
big and hard to follow.

Let's add subfunctions for each thing, diff ontop:

---
diff --git a/drivers/crypto/ccp/sev-dev.c b/drivers/crypto/ccp/sev-dev.c
index fa992ce57ffe..70aabd1d3d5f 100644
--- a/drivers/crypto/ccp/sev-dev.c
+++ b/drivers/crypto/ccp/sev-dev.c
@@ -759,6 +759,22 @@ static int __sev_snp_init_locked(int *error)
 	return rc;
 }
 
+static void __sev_platform_init_handle_tmr(struct sev_device *sev)
+{
+	if (sev_es_tmr)
+		return;
+
+	/* Obtain the TMR memory area for SEV-ES use */
+	sev_es_tmr = sev_fw_alloc(sev_es_tmr_size);
+	if (sev_es_tmr) {
+		/* Must flush the cache before giving it to the firmware */
+		if (!sev->snp_initialized)
+			clflush_cache_range(sev_es_tmr, sev_es_tmr_size);
+	} else {
+			dev_warn(sev->dev, "SEV: TMR allocation failed, SEV-ES support unavailable\n");
+	}
+}
+
 static int __sev_platform_init_locked(int *error)
 {
 	int rc, psp_ret = SEV_RET_NO_FW_CALL;
@@ -772,18 +788,7 @@ static int __sev_platform_init_locked(int *error)
 	if (sev->state == SEV_STATE_INIT)
 		return 0;
 
-	if (!sev_es_tmr) {
-		/* Obtain the TMR memory area for SEV-ES use */
-		sev_es_tmr = sev_fw_alloc(sev_es_tmr_size);
-		if (sev_es_tmr) {
-			/* Must flush the cache before giving it to the firmware */
-			if (!sev->snp_initialized)
-				clflush_cache_range(sev_es_tmr, sev_es_tmr_size);
-		} else {
-			dev_warn(sev->dev,
-				 "SEV: TMR allocation failed, SEV-ES support unavailable\n");
-		}
-	}
+	__sev_platform_init_handle_tmr(sev);
 
 	if (sev_init_ex_buffer) {
 		rc = sev_read_init_ex_file();

-- 
Regards/Gruss,
    Boris.

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