From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from linux.microsoft.com (linux.microsoft.com [13.77.154.182]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 14BB1468C39; Fri, 2 Oct 2026 21:58:56 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=13.77.154.182 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790978337; cv=none; b=uvIMxbBx6eVmQurqIJB1LBYLTv1gAuzc9m4lpUq2aMsZ0h6iXpbQWNgqEIGcuCga09k8PWF8FnKgqjjRdGp1MUIkt2SUSkdREp7vCbRp8Fa+/fTEMv3raplZxcHqK8Jyl9dXbfciIfFJulQqv9kAmdfYKN80MNRKrMjZ63lQK/A= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790978337; c=relaxed/simple; bh=Q/eBSYKHoTI/khO8eJCH1zEAGI5QnfUspyLuNSf8RXY=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=o4xGd/Geu99TKXeCSbdRm+tbjSn4FB0r1vcK8/xyfXQGXWhpynqj5cSWiYbP4PAS0DMj6tx0IlRmqAQliI/dcI9vHqrWCdEMrG8PvdiK7zJiWan4Dn69RjkuMujg4upoEFbI7aULR5woSWDBpVl/NTLDDn6eDwO29vAZV1L/8Ho= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.microsoft.com; spf=pass smtp.mailfrom=linux.microsoft.com; dkim=pass (1024-bit key) header.d=linux.microsoft.com header.i=@linux.microsoft.com header.b=FbIxTxN0; arc=none smtp.client-ip=13.77.154.182 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.microsoft.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.microsoft.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.microsoft.com header.i=@linux.microsoft.com header.b="FbIxTxN0" Received: from linuxonhyperv3.guj3yctzbm1etfxqx2vob5hsef.xx.internal.cloudapp.net (linux.microsoft.com [13.77.154.182]) by linux.microsoft.com (Postfix) with ESMTPSA id 00CAE20B716F; Fri, 2 Oct 2026 14:58:02 -0700 (PDT) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com 00CAE20B716F DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1790978282; bh=M+4fYoulF6eg59OIPkhRsd27IfbPeLczkS7f4QV9AjY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=FbIxTxN0GNi4C+Z5ccXfQZ01+sMzvVtyW08R5aCeXXAVVfyV8j0/w1fDzv5l0bH8I G8vmhLOgigjHAMYZK+mfdXvPUIMonW4NgE9eqJ3LOo+Q/tCD3tZ0LxiWETtAJHfXI9 qSseXv9vmvEI7aoUtW343s8r5nKXxaIPCo6ALuWQ= From: Kameron Carr To: haiyangz@microsoft.com, wei.liu@kernel.org, decui@microsoft.com, mhklinux@outlook.com Cc: catalin.marinas@arm.com, will@kernel.org, mark.rutland@arm.com, lpieralisi@kernel.org, sudeep.holla@kernel.org, arnd@arndb.de, thuth@redhat.com, linux-hyperv@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org Subject: [PATCH v5 4/6] Drivers: hv: Mark shared memory as decrypted for CCA Realms Date: Fri, 2 Oct 2026 14:57:23 -0700 Message-ID: <20261002215725.2015959-5-kameroncarr@linux.microsoft.com> X-Mailer: git-send-email 2.43.7 In-Reply-To: <20261002215725.2015959-1-kameroncarr@linux.microsoft.com> References: <20261002215725.2015959-1-kameroncarr@linux.microsoft.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 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 b1657cf..45ca8e2 100644 --- a/arch/arm64/hyperv/mshyperv.c +++ b/arch/arm64/hyperv/mshyperv.c @@ -158,3 +158,8 @@ 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