linux-kernel - [PATCH 6.1 085/138] KVM: SVM: enhance info printks in SEV init

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Date: Mon,  8 Apr 2024 14:58:19 +0200
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: stable@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	patches@...ts.linux.dev,
	Sean Christopherson <seanjc@...gle.com>,
	Paolo Bonzini <pbonzini@...hat.com>,
	Stéphane Graber <stgraber@...ntu.com>,
	kvm@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	Alexander Mikhalitsyn <aleksandr.mikhalitsyn@...onical.com>,
	Sasha Levin <sashal@...nel.org>
Subject: [PATCH 6.1 085/138] KVM: SVM: enhance info printks in SEV init

6.1-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@...onical.com>

[ Upstream commit 6d1bc9754b04075d938b47cf7f7800814b8911a7 ]

Let's print available ASID ranges for SEV/SEV-ES guests.
This information can be useful for system administrator
to debug if SEV/SEV-ES fails to enable.

There are a few reasons.
SEV:
- NPT is disabled (module parameter)
- CPU lacks some features (sev, decodeassists)
- Maximum SEV ASID is 0

SEV-ES:
- mmio_caching is disabled (module parameter)
- CPU lacks sev_es feature
- Minimum SEV ASID value is 1 (can be adjusted in BIOS/UEFI)

Cc: Sean Christopherson <seanjc@...gle.com>
Cc: Paolo Bonzini <pbonzini@...hat.com>
Cc: Stéphane Graber <stgraber@...ntu.com>
Cc: kvm@...r.kernel.org
Cc: linux-kernel@...r.kernel.org
Suggested-by: Sean Christopherson <seanjc@...gle.com>
Signed-off-by: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@...onical.com>
Link: https://lore.kernel.org/r/20230522161249.800829-3-aleksandr.mikhalitsyn@canonical.com
[sean: print '0' for min SEV-ES ASID if there are no available ASIDs]
Signed-off-by: Sean Christopherson <seanjc@...gle.com>
Stable-dep-of: 0aa6b90ef9d7 ("KVM: SVM: Add support for allowing zero SEV ASIDs")
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 arch/x86/kvm/svm/sev.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index 3dc0ee1fe9db9..1fe9257d87b2d 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -2217,7 +2217,6 @@ void __init sev_hardware_setup(void)
 	if (misc_cg_set_capacity(MISC_CG_RES_SEV, sev_asid_count))
 		goto out;
 
-	pr_info("SEV supported: %u ASIDs\n", sev_asid_count);
 	sev_supported = true;
 
 	/* SEV-ES support requested? */
@@ -2245,10 +2244,18 @@ void __init sev_hardware_setup(void)
 	if (misc_cg_set_capacity(MISC_CG_RES_SEV_ES, sev_es_asid_count))
 		goto out;
 
-	pr_info("SEV-ES supported: %u ASIDs\n", sev_es_asid_count);
 	sev_es_supported = true;
 
 out:
+	if (boot_cpu_has(X86_FEATURE_SEV))
+		pr_info("SEV %s (ASIDs %u - %u)\n",
+			sev_supported ? "enabled" : "disabled",
+			min_sev_asid, max_sev_asid);
+	if (boot_cpu_has(X86_FEATURE_SEV_ES))
+		pr_info("SEV-ES %s (ASIDs %u - %u)\n",
+			sev_es_supported ? "enabled" : "disabled",
+			min_sev_asid > 1 ? 1 : 0, min_sev_asid - 1);
+
 	sev_enabled = sev_supported;
 	sev_es_enabled = sev_es_supported;
 #endif
-- 
2.43.0