linux-kernel - [PATCH v7 2/3] KVM: SVM: Remove wbinvd in sev_vm

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Message-Id: <20250128015345.7929-3-szy0127@sjtu.edu.cn>
Date: Tue, 28 Jan 2025 09:53:44 +0800
From: Zheyun Shen <szy0127@...u.edu.cn>
To: thomas.lendacky@....com,
	seanjc@...gle.com,
	pbonzini@...hat.com,
	tglx@...utronix.de,
	kevinloughlin@...gle.com,
	mingo@...hat.com,
	bp@...en8.de
Cc: kvm@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	Zheyun Shen <szy0127@...u.edu.cn>
Subject: [PATCH v7 2/3] KVM: SVM: Remove wbinvd in sev_vm_destroy()

Before sev_vm_destroy() is called, kvm_arch_guest_memory_reclaimed()
has been called for SEV and SEV-ES and kvm_arch_gmem_invalidate()
has been called for SEV-SNP. These functions have already handled
flushing the memory. Therefore, this wbinvd_on_all_cpus() can
simply be dropped.

Suggested-by: Sean Christopherson <seanjc@...gle.com>
Signed-off-by: Zheyun Shen <szy0127@...u.edu.cn>
---
 arch/x86/kvm/svm/sev.c | 6 ------
 1 file changed, 6 deletions(-)

diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index 943bd074a..1ce67de9d 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -2899,12 +2899,6 @@ void sev_vm_destroy(struct kvm *kvm)
 		return;
 	}
 
-	/*
-	 * Ensure that all guest tagged cache entries are flushed before
-	 * releasing the pages back to the system for use. CLFLUSH will
-	 * not do this, so issue a WBINVD.
-	 */
-	wbinvd_on_all_cpus();
 
 	/*
 	 * if userspace was terminated before unregistering the memory regions
-- 
2.34.1