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 2BBCA3FE359; Thu, 1 Oct 2026 22:07:01 +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=1790892422; cv=none; b=k6ss9U8yAB8qApvxAZShkt9pVYT8IRsK84pyA5VztUDVTKE8U0NeeNxHNJsSy1AlN2fO18N5Gas7XnqKZJ+I7lVfMDB/h65YeAihpd1Heo5fjqRHgjeXwwt8fE16MMSV8IGl5/UUIwtRnLedn/8JvvVQr+lIPWOC9rXF2bbI63o= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790892422; c=relaxed/simple; bh=tza3pDjQaY+rxJTemxwjSWMFD36ykVq6n44oBhjSFz8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=EV77Pt9V0Mac9WzJD+a2YkHzG+XAG3C7LnnYUad2GKDvk1W/CPNEOkVNp50ijLej+ezOfPq42YBExo7UdAh5QnugwKtq+NKFXNdWeM5lJkm4KsBW8YD6BGIaZxE+LJHFsaoxMqoyvJRGgwhAYijBxibNc0AhNIEUIkstWA3uwsk= 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=BJbPuIcj; 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="BJbPuIcj" Received: from linuxonhyperv3.guj3yctzbm1etfxqx2vob5hsef.xx.internal.cloudapp.net (linux.microsoft.com [13.77.154.182]) by linux.microsoft.com (Postfix) with ESMTPSA id 8167420B7169; Thu, 1 Oct 2026 15:06:07 -0700 (PDT) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com 8167420B7169 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1790892367; bh=b2GtJHBzDcmYlbHghwmtxMILKeFIMO+Ff8lGch7jV0Q=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=BJbPuIcjxMBAYkMktPIu2maIW6+tCNmB9K2qkTawvVeAE6Nlcnkx3PZ/rUHkCUmN3 4LJ55SnH8Xgs+zJsw1NXGfrZ2H7xzkPjW4EpCwEWQ+B5BThOdK90BDAR9jiCrRlZll 7pb5gj819hfLrZWJUSXZB/zLBjEPqMcFSi0zH/Mk= From: Kameron Carr To: kys@microsoft.com, haiyangz@microsoft.com, wei.liu@kernel.org, decui@microsoft.com, longli@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 v4 3/6] arm64: hyperv: Add per-CPU RSI host call infrastructure for CCA Realms Date: Thu, 1 Oct 2026 15:05:49 -0700 Message-ID: <20261001220552.1793471-4-kameroncarr@linux.microsoft.com> X-Mailer: git-send-email 2.43.7 In-Reply-To: <20261001220552.1793471-1-kameroncarr@linux.microsoft.com> References: <20261001220552.1793471-1-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 Arm CCA Realms cannot issue Hyper-V hypercalls via HVC; the guest must route them through the RSI_HOST_CALL interface, which takes the IPA of a per-CPU rsi_host_call structure as its argument. Add hv_hostcall_array as a per-CPU struct array and allocate it during hyperv_init(). The allocation is gated on is_realm_world() so non-Realm arm64 Hyper-V guests pay no memory cost. Reviewed-by: Michael Kelley Signed-off-by: Kameron Carr --- arch/arm64/hyperv/mshyperv.c | 28 ++++++++++++++++++++++++++-- arch/arm64/include/asm/mshyperv.h | 4 ++++ 2 files changed, 30 insertions(+), 2 deletions(-) diff --git a/arch/arm64/hyperv/mshyperv.c b/arch/arm64/hyperv/mshyperv.c index 4fdc26a..b1657cf 100644 --- a/arch/arm64/hyperv/mshyperv.c +++ b/arch/arm64/hyperv/mshyperv.c @@ -11,14 +11,19 @@ #include #include +#include #include #include +#include #include #include #include static bool hyperv_initialized; +struct rsi_host_call *hv_hostcall_array; +EXPORT_SYMBOL_GPL(hv_hostcall_array); + int hv_get_hypervisor_version(union hv_hypervisor_version_info *info) { hv_get_vpreg_128(HV_REGISTER_HYPERVISOR_VERSION, @@ -85,6 +90,20 @@ static int __init hyperv_init(void) if (!hyperv_detect_via_acpi() && !hyperv_detect_via_smccc()) return 0; + /* + * The RSI host-call buffers are only ever used when + * is_realm_world() is true. Skip the allocation on non-Realm + * guests. A single contiguous array of nr_cpu_ids entries is + * allocated; each CPU indexes into it by its processor ID. + */ + if (is_realm_world()) { + hv_hostcall_array = kcalloc(nr_cpu_ids, + sizeof(struct rsi_host_call), + GFP_KERNEL); + if (!hv_hostcall_array) + return -ENOMEM; + } + /* Setup the guest ID */ guest_id = hv_generate_guest_id(LINUX_VERSION_CODE); hv_set_vpreg(HV_REGISTER_GUEST_OS_ID, guest_id); @@ -106,13 +125,13 @@ static int __init hyperv_init(void) ret = hv_common_init(); if (ret) - return ret; + goto free_hostcall_mem; ret = cpuhp_setup_state(CPUHP_AP_HYPERV_ONLINE, "arm64/hyperv_init:online", hv_common_cpu_init, hv_common_cpu_die); if (ret < 0) { hv_common_free(); - return ret; + goto free_hostcall_mem; } if (ms_hyperv.priv_high & HV_ACCESS_PARTITION_ID) @@ -125,6 +144,11 @@ static int __init hyperv_init(void) hyperv_initialized = true; return 0; + +free_hostcall_mem: + kfree(hv_hostcall_array); + hv_hostcall_array = NULL; + return ret; } early_initcall(hyperv_init); diff --git a/arch/arm64/include/asm/mshyperv.h b/arch/arm64/include/asm/mshyperv.h index b721d31..aed0aa5 100644 --- a/arch/arm64/include/asm/mshyperv.h +++ b/arch/arm64/include/asm/mshyperv.h @@ -61,6 +61,10 @@ static inline u64 hv_get_non_nested_msr(unsigned int reg) ARM_SMCCC_OWNER_VENDOR_HYP, \ HV_SMCCC_FUNC_NUMBER) +/* Per-CPU-indexed RSI host call structures for CCA Realms */ +struct rsi_host_call; +extern struct rsi_host_call *hv_hostcall_array; + #include #endif -- 2.45.4