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From: Sean Christopherson <seanjc@google.com>
To: Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
	 Dave Hansen <dave.hansen@linux.intel.com>,
	x86@kernel.org,  Sean Christopherson <seanjc@google.com>,
	Paolo Bonzini <pbonzini@redhat.com>
Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
	 Zheyun Shen <szy0127@sjtu.edu.cn>,
	Tom Lendacky <thomas.lendacky@amd.com>,
	 Kevin Loughlin <kevinloughlin@google.com>,
	Mingwei Zhang <mizhang@google.com>
Subject: [PATCH 1/7] KVM: SVM: Remove wbinvd in sev_vm_destroy()
Date: Wed, 26 Feb 2025 17:48:52 -0800	[thread overview]
Message-ID: <20250227014858.3244505-2-seanjc@google.com> (raw)
In-Reply-To: <20250227014858.3244505-1-seanjc@google.com>

From: Zheyun Shen <szy0127@sjtu.edu.cn>

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@google.com>
Signed-off-by: Zheyun Shen <szy0127@sjtu.edu.cn>
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
---
 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 74525651770a..d934d788ac39 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -2879,12 +2879,6 @@ 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
-- 
2.48.1.711.g2feabab25a-goog


  reply	other threads:[~2025-02-27  1:49 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-02-27  1:48 [PATCH 0/7] x86, KVM: Optimize SEV cache flushing Sean Christopherson
2025-02-27  1:48 ` Sean Christopherson [this message]
2025-02-27  1:48 ` [PATCH 2/7] x86, lib: Drop the unused return value from wbinvd_on_all_cpus() Sean Christopherson
2025-02-27 19:59   ` Sean Christopherson
2025-02-27  1:48 ` [PATCH 3/7] x86, lib: Add WBNOINVD helper functions Sean Christopherson
2025-03-13 10:13   ` Huang, Kai
2025-02-27  1:48 ` [PATCH 4/7] KVM: SEV: Prefer WBNOINVD over WBINVD for cache maintenance efficiency Sean Christopherson
2025-02-27  1:48 ` [PATCH 5/7] KVM: x86: Use wbinvd_on_cpu() instead of an open-coded equivalent Sean Christopherson
2025-03-03 16:49   ` Tom Lendacky
2025-02-27  1:48 ` [PATCH 6/7] x86, lib: Add wbinvd and wbnoinvd helpers to target multiple CPUs Sean Christopherson
2025-02-27 12:45   ` Zheyun Shen
2025-03-13 10:19   ` Huang, Kai
2025-02-27  1:48 ` [PATCH 7/7] KVM: SVM: Flush cache only on CPUs running SEV guest Sean Christopherson
2025-03-03 16:53   ` Tom Lendacky
2025-03-03 16:46 ` [PATCH 0/7] x86, KVM: Optimize SEV cache flushing Tom Lendacky

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