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charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20260428-gmem-inplace-conversion-v5-20-d8608ccfca22@google.com> References: <20260428-gmem-inplace-conversion-v5-0-d8608ccfca22@google.com> In-Reply-To: <20260428-gmem-inplace-conversion-v5-0-d8608ccfca22@google.com> To: aik@amd.com, andrew.jones@linux.dev, binbin.wu@linux.intel.com, brauner@kernel.org, chao.p.peng@linux.intel.com, david@kernel.org, ira.weiny@intel.com, jmattson@google.com, jthoughton@google.com, michael.roth@amd.com, oupton@kernel.org, pankaj.gupta@amd.com, qperret@google.com, rick.p.edgecombe@intel.com, rientjes@google.com, shivankg@amd.com, steven.price@arm.com, tabba@google.com, willy@infradead.org, wyihan@google.com, yan.y.zhao@intel.com, forkloop@google.com, pratyush@kernel.org, suzuki.poulose@arm.com, aneesh.kumar@kernel.org, Paolo Bonzini , Sean Christopherson , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H. Peter Anvin" , Steven Rostedt , Masami Hiramatsu , Mathieu Desnoyers , Jonathan Corbet , Shuah Khan , Shuah Khan , Vishal Annapurve , Andrew Morton , Chris Li , Kairui Song , Kemeng Shi , Nhat Pham , Baoquan He , Barry Song , Axel Rasmussen , Yuanchu Xie , Wei Xu , Youngjun Park , Qi Zheng , Shakeel Butt , Kiryl Shutsemau , Jason Gunthorpe , Vlastimil Babka Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-mm@kvack.org, linux-coco@lists.linux.dev, Ackerley Tng X-Mailer: b4 0.14.3 X-Developer-Signature: v=1; a=ed25519-sha256; t=1777418714; l=1390; i=ackerleytng@google.com; s=20260225; h=from:subject:message-id; bh=9LP/svD9TvgxKqvednNMupCSsWJ+AFS+3tUCHtCnRqA=; b=7TverXUJlngRxhJ4vEWJkucYIO7XShyfSISUb/HZPT3irzIwFpodwZIaXKo0xt09LhSOu99cl vzzDW2Ybw7TASLiyA7ny4f0JXMSI7+HJSNDTw51rwwdQnOzO+yzu59J X-Developer-Key: i=ackerleytng@google.com; a=ed25519; pk=sAZDYXdm6Iz8FHitpHeFlCMXwabodTm7p8/3/8xUxuU= X-Endpoint-Received: by B4 Relay for ackerleytng@google.com/20260225 with auth_id=649 X-Original-From: Ackerley Tng Reply-To: ackerleytng@google.com X-Stat-Signature: yo53wygdgj3fww1phhga3dyjgyhqmaf7 X-Rspamd-Queue-Id: 7A27740004 X-Rspam-User: X-Rspamd-Server: rspam08 X-HE-Tag: 1777418727-902978 X-HE-Meta: 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 81i3lsqI /ZFFcVgWrlTCzYT13mN49R37qO6zRNaB2hJtoov4a+uALSn7dIEZc5JaUGufe8VM7VI9WoiSkFqyXQF9B2m1ZHBuxa+j2VfJ6YRYsDskQz2VetiCz3vGZ9LTT90iEb/DqVXIlkrzYWsdLsXV5GE6fmV0AA2L/FVgMPjVj+rTBWzF3Lroe6BI4ZNxjwrxBcKQtQRvTIiEJPgBTSBcZ+jdyOAayw3X2JNjNop6BQ+Gc/TCw5tXjpUYKROlVGgi48UL/LuZn707V2zcIEWB2OsMu7b0eldPcPuYHQhQrlcIZYAeF9ZkCPENn+rbTvTXuHbn1f5/qxPGuWNGx+E5QJ1JPmEH5lR1YJqn50xltXGRByC/VLuNnyJGYTdfQiJKB3bHsBDVv6mXblAhywLoU0SQyBVt7fLAh91u7vmwotdcA1YGn+Nh4Q+KZnnEuVWRReuY/3n0eGVztNbiW1PImZWS2OXcxFQ== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: From: Sean Christopherson Now that guest_memfd supports tracking private vs. shared within gmem itself, allow userspace to specify INIT_SHARED on a guest_memfd instance for x86 Confidential Computing (CoCo) VMs, so long as per-VM attributes are disabled, i.e. when it's actually possible for a guest_memfd instance to contain shared memory. Signed-off-by: Sean Christopherson Signed-off-by: Ackerley Tng --- arch/x86/kvm/x86.c | 11 +++++------ 1 file changed, 5 insertions(+), 6 deletions(-) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 1560de1e95be0..6609957ecfea3 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -14172,14 +14172,13 @@ bool kvm_arch_no_poll(struct kvm_vcpu *vcpu) } #ifdef CONFIG_KVM_GUEST_MEMFD -/* - * KVM doesn't yet support initializing guest_memfd memory as shared for VMs - * with private memory (the private vs. shared tracking needs to be moved into - * guest_memfd). - */ bool kvm_arch_supports_gmem_init_shared(struct kvm *kvm) { - return !kvm_arch_has_private_mem(kvm); + /* + * INIT_SHARED isn't supported if the memory attributes are per-VM, + * in which case guest_memfd can _only_ be used for private memory. + */ + return !vm_memory_attributes || !kvm_arch_has_private_mem(kvm); } #ifdef CONFIG_HAVE_KVM_ARCH_GMEM_PREPARE -- 2.54.0.545.g6539524ca2-goog