From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 72DF6606A31D for ; Sat, 31 Oct 2026 00:15:03 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=lists.infradead.org header.i=@lists.infradead.org header.a=rsa-sha256 header.s=bombadil.20210309 header.b=Yar2I8Ao; dkim=pass (1024-bit key, unprotected) header.d=linux.microsoft.com header.i=@linux.microsoft.com header.a=rsa-sha256 header.s=default header.b=P+ekTsJ/ DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-ID:Date:Subject:Cc:To:From: Reply-To:Content-Type:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Unsubscribe-Post: List-Owner; bh=kQ5/8xbFXcvnPBvtpcGqH1Rld8p6e60w+RwWV7HqUUY=; b=Yar2I8AoHB4Goh jWtF5/PoyaFnBHrQYgcMsuIAi4de4ibCGJEpzQuzYbU9N9ovk8YzmHlWPQ1H/Fu00GomDuZ2vWGxh puo/35QVtHxXar+uVfkB+7owdkedUgtoY8mC5Uwj+wImPM950G908q42NHqAAmcOYbNr60st2xcX+ i7ktxd0LiBLaze+x/u0cZnoG7xagbPJVPpb+1k8BXw9HH1X7yUoU6xelxFIaN1d9Ns5D7t78ThQi0 gwpKCVN/mzOM5pZWrKImkoEVABYGj3XKghKVQWnpLt+mXiKnpuvH05t9UDiJm/dnvYX1yLBOBVOnj bBiFArDdWQg28p6kH+5A==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.100.1 #2 (Red Hat Linux)) id 1xMwkH-0000000Clhj-2wY2; Sat, 31 Oct 2026 00:14:53 +0000 Received: from linux.microsoft.com ([13.77.154.182]) by bombadil.infradead.org with esmtp (Exim 4.100.1 #2 (Red Hat Linux)) id 1xMwk5-0000000CldZ-01Ho for linux-arm-kernel@lists.infradead.org; Sat, 31 Oct 2026 00:14:42 +0000 Received: from linuxonhyperv3.guj3yctzbm1etfxqx2vob5hsef.xx.internal.cloudapp.net (linux.microsoft.com [13.77.154.182]) by linux.microsoft.com (Postfix) with ESMTPSA id 013DB20B716E; Fri, 30 Oct 2026 17:14:27 -0700 (PDT) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com 013DB20B716E DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1793405667; bh=kQ5/8xbFXcvnPBvtpcGqH1Rld8p6e60w+RwWV7HqUUY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=P+ekTsJ/opLRlBEuR94J9UjkhCsMFfvbJjvtZq0w5TiN+3cUChC2aO680+dVW09+I 2hdyQHwno/0Pb+ZYwbxTcIKDd4brQJqsI//6Z7wH7IH4z3rTgNTJPrI02KpISZtYwH 20LERihtY+OHRaORU8w9VUVm+0X4/W2rHEUtg4v8= From: Kameron Carr To: decui@microsoft.com, haiyangz@microsoft.com, mhklinux@outlook.com, wei.liu@kernel.org Cc: arnd@arndb.de, catalin.marinas@arm.com, linux-arch@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-hyperv@vger.kernel.org, linux-kernel@vger.kernel.org, lpieralisi@kernel.org, mark.rutland@arm.com, sudeep.holla@kernel.org, thuth@redhat.com, will@kernel.org Subject: [PATCH v6 4/6] Drivers: hv: Mark shared memory as decrypted for CCA Realms Date: Fri, 30 Oct 2026 17:14:10 -0700 Message-ID: <20261031001412.4150488-5-kameroncarr@linux.microsoft.com> X-Mailer: git-send-email 2.43.7 In-Reply-To: <20261031001412.4150488-1-kameroncarr@linux.microsoft.com> References: <20261031001412.4150488-1-kameroncarr@linux.microsoft.com> X-Archived-By: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Spam-Status: No, score=-18.9 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=4.0.1 X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20261030_171441_315038_BBAE4F1F X-CRM114-Status: GOOD ( 12.03 ) X-Spam-Score: -2.1 (--) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" In hv_common_cpu_init(), the per-CPU hypercall input/output pages need to be marked as decrypted (shared) for confidential VM isolation types. This is already done for SNP and TDX isolation; extend the same handling to Arm CCA Realm guests so that the host hypervisor can access the shared hypercall buffers. is_realm_world() is declared in include/linux/arm-rsi-cmds.h which only builds on arm64 (it includes ), so using it directly in the arch-neutral drivers/hv/hv_common.c would break the x86 build. Introduce a Hyper-V-specific helper following the established hv_isolation_type_snp() / hv_isolation_type_tdx() pattern. On architectures other than arm64 the weak default keeps the existing behaviour. Reviewed-by: Michael Kelley Signed-off-by: Kameron Carr --- arch/arm64/hyperv/mshyperv.c | 5 +++++ drivers/hv/hv_common.c | 17 +++++++++++++---- include/asm-generic/mshyperv.h | 1 + 3 files changed, 19 insertions(+), 4 deletions(-) diff --git a/arch/arm64/hyperv/mshyperv.c b/arch/arm64/hyperv/mshyperv.c index 46ab2da..da6c3aa0 100644 --- a/arch/arm64/hyperv/mshyperv.c +++ b/arch/arm64/hyperv/mshyperv.c @@ -182,3 +182,8 @@ bool hv_is_hyperv_initialized(void) return hyperv_initialized; } EXPORT_SYMBOL_GPL(hv_is_hyperv_initialized); + +bool hv_isolation_type_cca(void) +{ + return is_realm_world(); +} diff --git a/drivers/hv/hv_common.c b/drivers/hv/hv_common.c index 31256cb..a60c92c 100644 --- a/drivers/hv/hv_common.c +++ b/drivers/hv/hv_common.c @@ -476,6 +476,7 @@ int hv_common_cpu_init(unsigned int cpu) u64 msr_vp_index; gfp_t flags; const int pgcount = hv_output_page_exists() ? 2 : 1; + const size_t alloc_size = ALIGN((size_t)pgcount * HV_HYP_PAGE_SIZE, PAGE_SIZE); void *mem; int ret = 0; @@ -489,7 +490,7 @@ int hv_common_cpu_init(unsigned int cpu) * online and then taken offline */ if (!*inputarg) { - mem = kmalloc_array(pgcount, HV_HYP_PAGE_SIZE, flags); + mem = kmalloc(alloc_size, flags); if (!mem) return -ENOMEM; @@ -499,14 +500,16 @@ int hv_common_cpu_init(unsigned int cpu) } if (!ms_hyperv.paravisor_present && - (hv_isolation_type_snp() || hv_isolation_type_tdx())) { - ret = set_memory_decrypted((unsigned long)mem, pgcount); + (hv_isolation_type_snp() || hv_isolation_type_tdx() || + hv_isolation_type_cca())) { + ret = set_memory_decrypted((unsigned long)mem, + alloc_size >> PAGE_SHIFT); if (ret) { /* It may be unsafe to free 'mem' */ return ret; } - memset(mem, 0x00, pgcount * HV_HYP_PAGE_SIZE); + memset(mem, 0x00, alloc_size); } /* @@ -666,6 +669,12 @@ bool __weak hv_isolation_type_tdx(void) } EXPORT_SYMBOL_GPL(hv_isolation_type_tdx); +bool __weak hv_isolation_type_cca(void) +{ + return false; +} +EXPORT_SYMBOL_GPL(hv_isolation_type_cca); + void __weak hv_setup_vmbus_handler(void (*handler)(void)) { } diff --git a/include/asm-generic/mshyperv.h b/include/asm-generic/mshyperv.h index bf601d6..1fa79ab 100644 --- a/include/asm-generic/mshyperv.h +++ b/include/asm-generic/mshyperv.h @@ -79,6 +79,7 @@ u64 hv_do_fast_hypercall16(u16 control, u64 input1, u64 input2); bool hv_isolation_type_snp(void); bool hv_isolation_type_tdx(void); +bool hv_isolation_type_cca(void); /* * On architectures where Hyper-V doesn't support AEOI (e.g., ARM64), -- 2.45.4