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From: Wei Huang <wei.huang2@amd.com>
To: kvm@vger.kernel.org
Cc: linux-kernel@vger.kernel.org, pbonzini@redhat.com,
	vkuznets@redhat.com, seanjc@google.com, wanpengli@tencent.com,
	jmattson@google.com, joro@8bytes.org, tglx@linutronix.de,
	mingo@redhat.com, bp@alien8.de, x86@kernel.org, hpa@zytor.com,
	wei.huang2@amd.com
Subject: [PATCH v3 3/3] KVM: SVM: Add 5-level page table support for SVM
Date: Wed, 18 Aug 2021 11:55:49 -0500	[thread overview]
Message-ID: <20210818165549.3771014-4-wei.huang2@amd.com> (raw)
In-Reply-To: <20210818165549.3771014-1-wei.huang2@amd.com>

When the 5-level page table is enabled on host OS, the nested page table
for guest VMs must use 5-level as well. Update get_npt_level() function
to reflect this requirement. In the meanwhile, remove the code that
prevents kvm-amd driver from being loaded when 5-level page table is
detected.

Signed-off-by: Wei Huang <wei.huang2@amd.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 arch/x86/kvm/svm/svm.c | 9 +++------
 1 file changed, 3 insertions(+), 6 deletions(-)

diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index b34840a2ffa7..ecc4bb8e4ea0 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -261,7 +261,9 @@ u32 svm_msrpm_offset(u32 msr)
 static int get_max_npt_level(void)
 {
 #ifdef CONFIG_X86_64
-	return PT64_ROOT_4LEVEL;
+	bool la57 = (cr4_read_shadow() & X86_CR4_LA57) != 0;
+
+	return la57 ? PT64_ROOT_5LEVEL : PT64_ROOT_4LEVEL;
 #else
 	return PT32E_ROOT_LEVEL;
 #endif
@@ -462,11 +464,6 @@ static int has_svm(void)
 		return 0;
 	}
 
-	if (pgtable_l5_enabled()) {
-		pr_info("KVM doesn't yet support 5-level paging on AMD SVM\n");
-		return 0;
-	}
-
 	return 1;
 }
 
-- 
2.31.1


  parent reply	other threads:[~2021-08-18 16:56 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-18 16:55 [PATCH v3 0/3] SVM 5-level page table support Wei Huang
2021-08-18 16:55 ` [PATCH v3 1/3] KVM: x86: Allow CPU to force vendor-specific TDP level Wei Huang
2021-08-18 16:55 ` [PATCH v3 2/3] KVM: x86: Handle the case of 5-level shadow page table Wei Huang
2021-08-18 17:15   ` Sean Christopherson
2021-08-19 16:36     ` Paolo Bonzini
2021-08-18 18:00   ` Tom Lendacky
2021-08-18 16:55 ` Wei Huang [this message]
2021-08-18 17:32   ` [PATCH v3 3/3] KVM: SVM: Add 5-level page table support for SVM Sean Christopherson
2021-08-19 16:38     ` Paolo Bonzini
2021-08-19 16:43 ` [PATCH v3 0/3] SVM 5-level page table support Paolo Bonzini
2021-08-23  9:20   ` Maxim Levitsky
2021-08-23 15:15     ` Wei Huang
2021-08-23 16:10       ` Sean Christopherson
2021-08-23 18:10         ` Maxim Levitsky
2021-08-23 18:06       ` Maxim Levitsky

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