From nobody Fri Oct 3 18:01:17 2025 Received: from linux.microsoft.com (linux.microsoft.com [13.77.154.182]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 84A39153BE8; Thu, 28 Aug 2025 01:06:01 +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=1756343163; cv=none; b=E51ttRR60pgHzjbBQLkIUeqGbbsNKuwcP3Gble+5VA3pOr2zQ1i0nnDrExE+EzuTeqVgd2yEmgCS7ZpKGWvk2wlV6+BPeRQeIl8gxX/PHelmJ3nMndISWcQriODMgg4w9SE4Yc1sCQffchBOTpJyg/XeT18KxoHpzfnw9KXIUWg= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756343163; c=relaxed/simple; bh=gX0ryYRPHtElZ1hllAXKlj3yrn+fIX8UyZqIcK3jzeA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=hntkgVrKVnmt1G1H4ksR8IfLPKfaoE2TuEP2wF5fk3rFJA3n6JmAS69oYYQb6KTbagtfJqmsR5MtqQ4BmrZPdJ/OqgYgJz79tIGONC+NmxxfZOEGxtPPof0H04FBHeJKEsxGlxLMBO0wbvuVarfY6FzjUHoi9UAgglFPfckgEkE= 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=SUGJnMem; 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="SUGJnMem" Received: from romank-3650.corp.microsoft.com (unknown [131.107.174.60]) by linux.microsoft.com (Postfix) with ESMTPSA id 6F6462110803; Wed, 27 Aug 2025 18:06:00 -0700 (PDT) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com 6F6462110803 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1756343160; bh=L6UzI1NEI3CsxJslYWLm1pMyIYiQMLPOOt/vIq7wad0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=SUGJnMemMWGrvS6SeVWMwRZBJ8UcOKuABgfC+JR373F8jwMF5B91/tLb8COJKMH2C 7e3ie/n5XEEDAX6rWgZIuut0EenBfJxpfNZpjiTU5oHNbVU/yaykgyNDQn8JvymVR+ 80EMcsCoEbZy5Bp3d1jDmPOii3fw4c6ajWRHNyqI= From: Roman Kisel To: arnd@arndb.de, bp@alien8.de, corbet@lwn.net, dave.hansen@linux.intel.com, decui@microsoft.com, haiyangz@microsoft.com, hpa@zytor.com, kys@microsoft.com, mikelley@microsoft.com, mingo@redhat.com, tglx@linutronix.de, Tianyu.Lan@microsoft.com, wei.liu@kernel.org, x86@kernel.org, linux-hyperv@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org Cc: benhill@microsoft.com, bperkins@microsoft.com, sunilmut@microsoft.com, romank@linux.microsoft.com Subject: [PATCH hyperv-next v5 02/16] drivers: hv: VMBus protocol version 6.0 Date: Wed, 27 Aug 2025 18:05:43 -0700 Message-ID: <20250828010557.123869-3-romank@linux.microsoft.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20250828010557.123869-1-romank@linux.microsoft.com> References: <20250828010557.123869-1-romank@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: quoted-printable Content-Type: text/plain; charset="utf-8" The confidential VMBus is supported starting from the protocol version 6.0 onwards. Update the relevant definitions, provide the x86-specific way to detect availability of the Confidential VMBus and provide a function that returns whether VMBus is confidential or not. No functional changes. Signed-off-by: Roman Kisel Reviewed-by: Alok Tiwari Reviewed-by: Michael Kelley --- arch/x86/kernel/cpu/mshyperv.c | 19 ++++++++++ drivers/hv/hv_common.c | 6 +++ drivers/hv/hyperv_vmbus.h | 2 + drivers/hv/vmbus_drv.c | 12 ++++++ include/asm-generic/mshyperv.h | 1 + include/hyperv/hvgdk_mini.h | 1 + include/linux/hyperv.h | 69 ++++++++++++++++++++++++---------- 7 files changed, 91 insertions(+), 19 deletions(-) diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c index 25773af116bc..95cd78004b11 100644 --- a/arch/x86/kernel/cpu/mshyperv.c +++ b/arch/x86/kernel/cpu/mshyperv.c @@ -90,6 +90,25 @@ void hv_set_non_nested_msr(unsigned int reg, u64 value) } EXPORT_SYMBOL_GPL(hv_set_non_nested_msr); =20 +/* + * Detect if the confidential VMBus is available. + */ +bool hv_confidential_vmbus_available(void) +{ + u32 eax; + + eax =3D cpuid_eax(HYPERV_CPUID_VIRT_STACK_INTERFACE); + if (eax !=3D HYPERV_VS_INTERFACE_EAX_SIGNATURE) + return false; + + eax =3D cpuid_eax(HYPERV_CPUID_VIRT_STACK_PROPERTIES); + + /* + * The paravisor may set the bit in the hardware confidential VMs. + */ + return eax & HYPERV_VS_PROPERTIES_EAX_CONFIDENTIAL_VMBUS_AVAILABLE; +} + u64 hv_get_msr(unsigned int reg) { if (hv_nested) diff --git a/drivers/hv/hv_common.c b/drivers/hv/hv_common.c index 8836cf9fad40..fae63c54e531 100644 --- a/drivers/hv/hv_common.c +++ b/drivers/hv/hv_common.c @@ -716,6 +716,12 @@ u64 __weak hv_tdx_hypercall(u64 control, u64 param1, u= 64 param2) } EXPORT_SYMBOL_GPL(hv_tdx_hypercall); =20 +bool __weak hv_confidential_vmbus_available(void) +{ + return false; +} +EXPORT_SYMBOL_GPL(hv_confidential_vmbus_available); + void hv_identify_partition_type(void) { /* Assume guest role */ diff --git a/drivers/hv/hyperv_vmbus.h b/drivers/hv/hyperv_vmbus.h index b61f01fc1960..6e4c3acc1169 100644 --- a/drivers/hv/hyperv_vmbus.h +++ b/drivers/hv/hyperv_vmbus.h @@ -334,6 +334,8 @@ extern const struct vmbus_channel_message_table_entry =20 /* General vmbus interface */ =20 +bool vmbus_is_confidential(void); + struct hv_device *vmbus_device_create(const guid_t *type, const guid_t *instance, struct vmbus_channel *channel); diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c index a366365f2c49..8d9488c3174d 100644 --- a/drivers/hv/vmbus_drv.c +++ b/drivers/hv/vmbus_drv.c @@ -57,6 +57,18 @@ static long __percpu *vmbus_evt; int vmbus_irq; int vmbus_interrupt; =20 +/* + * If the Confidential VMBus is used, the data on the "wire" is not + * visible to either the host or the hypervisor. + */ +static bool is_confidential; + +bool vmbus_is_confidential(void) +{ + return is_confidential; +} +EXPORT_SYMBOL_GPL(vmbus_is_confidential); + /* * The panic notifier below is responsible solely for unloading the * vmbus connection, which is necessary in a panic event. diff --git a/include/asm-generic/mshyperv.h b/include/asm-generic/mshyperv.h index dbd4c2f3aee3..acb017f6c423 100644 --- a/include/asm-generic/mshyperv.h +++ b/include/asm-generic/mshyperv.h @@ -332,6 +332,7 @@ bool hv_is_hibernation_supported(void); enum hv_isolation_type hv_get_isolation_type(void); bool hv_is_isolation_supported(void); bool hv_isolation_type_snp(void); +bool hv_confidential_vmbus_available(void); u64 hv_ghcb_hypercall(u64 control, void *input, void *output, u32 input_si= ze); u64 hv_tdx_hypercall(u64 control, u64 param1, u64 param2); void hyperv_cleanup(void); diff --git a/include/hyperv/hvgdk_mini.h b/include/hyperv/hvgdk_mini.h index 79b7324e4ef5..4b189f9d39cb 100644 --- a/include/hyperv/hvgdk_mini.h +++ b/include/hyperv/hvgdk_mini.h @@ -260,6 +260,7 @@ union hv_hypervisor_version_info { #define HYPERV_CPUID_VIRT_STACK_PROPERTIES 0x40000082 /* Support for the extended IOAPIC RTE format */ #define HYPERV_VS_PROPERTIES_EAX_EXTENDED_IOAPIC_RTE BIT(2) +#define HYPERV_VS_PROPERTIES_EAX_CONFIDENTIAL_VMBUS_AVAILABLE BIT(3) =20 #define HYPERV_HYPERVISOR_PRESENT_BIT 0x80000000 #define HYPERV_CPUID_MIN 0x40000005 diff --git a/include/linux/hyperv.h b/include/linux/hyperv.h index a59c5c3e95fb..a1820fabbfc0 100644 --- a/include/linux/hyperv.h +++ b/include/linux/hyperv.h @@ -265,16 +265,18 @@ static inline u32 hv_get_avail_to_write_percent( * Linux kernel. */ =20 -#define VERSION_WS2008 ((0 << 16) | (13)) -#define VERSION_WIN7 ((1 << 16) | (1)) -#define VERSION_WIN8 ((2 << 16) | (4)) -#define VERSION_WIN8_1 ((3 << 16) | (0)) -#define VERSION_WIN10 ((4 << 16) | (0)) -#define VERSION_WIN10_V4_1 ((4 << 16) | (1)) -#define VERSION_WIN10_V5 ((5 << 16) | (0)) -#define VERSION_WIN10_V5_1 ((5 << 16) | (1)) -#define VERSION_WIN10_V5_2 ((5 << 16) | (2)) -#define VERSION_WIN10_V5_3 ((5 << 16) | (3)) +#define VMBUS_MAKE_VERSION(MAJ, MIN) ((((u32)MAJ) << 16) | (MIN)) +#define VERSION_WS2008 VMBUS_MAKE_VERSION(0, 13) +#define VERSION_WIN7 VMBUS_MAKE_VERSION(1, 1) +#define VERSION_WIN8 VMBUS_MAKE_VERSION(2, 4) +#define VERSION_WIN8_1 VMBUS_MAKE_VERSION(3, 0) +#define VERSION_WIN10 VMBUS_MAKE_VERSION(4, 0) +#define VERSION_WIN10_V4_1 VMBUS_MAKE_VERSION(4, 1) +#define VERSION_WIN10_V5 VMBUS_MAKE_VERSION(5, 0) +#define VERSION_WIN10_V5_1 VMBUS_MAKE_VERSION(5, 1) +#define VERSION_WIN10_V5_2 VMBUS_MAKE_VERSION(5, 2) +#define VERSION_WIN10_V5_3 VMBUS_MAKE_VERSION(5, 3) +#define VERSION_WIN10_V6_0 VMBUS_MAKE_VERSION(6, 0) =20 /* Make maximum size of pipe payload of 16K */ #define MAX_PIPE_DATA_PAYLOAD (sizeof(u8) * 16384) @@ -335,14 +337,22 @@ struct vmbus_channel_offer { } __packed; =20 /* Server Flags */ -#define VMBUS_CHANNEL_ENUMERATE_DEVICE_INTERFACE 1 -#define VMBUS_CHANNEL_SERVER_SUPPORTS_TRANSFER_PAGES 2 -#define VMBUS_CHANNEL_SERVER_SUPPORTS_GPADLS 4 -#define VMBUS_CHANNEL_NAMED_PIPE_MODE 0x10 -#define VMBUS_CHANNEL_LOOPBACK_OFFER 0x100 -#define VMBUS_CHANNEL_PARENT_OFFER 0x200 -#define VMBUS_CHANNEL_REQUEST_MONITORED_NOTIFICATION 0x400 -#define VMBUS_CHANNEL_TLNPI_PROVIDER_OFFER 0x2000 +#define VMBUS_CHANNEL_ENUMERATE_DEVICE_INTERFACE 0x0001 +/* + * This flag indicates that the channel is offered by the paravisor, and m= ust + * use encrypted memory for the channel ring buffer. + */ +#define VMBUS_CHANNEL_CONFIDENTIAL_RING_BUFFER 0x0002 +/* + * This flag indicates that the channel is offered by the paravisor, and m= ust + * use encrypted memory for GPA direct packets and additional GPADLs. + */ +#define VMBUS_CHANNEL_CONFIDENTIAL_EXTERNAL_MEMORY 0x0004 +#define VMBUS_CHANNEL_NAMED_PIPE_MODE 0x0010 +#define VMBUS_CHANNEL_LOOPBACK_OFFER 0x0100 +#define VMBUS_CHANNEL_PARENT_OFFER 0x0200 +#define VMBUS_CHANNEL_REQUEST_MONITORED_NOTIFICATION 0x0400 +#define VMBUS_CHANNEL_TLNPI_PROVIDER_OFFER 0x2000 =20 struct vmpacket_descriptor { u16 type; @@ -621,6 +631,12 @@ struct vmbus_channel_relid_released { u32 child_relid; } __packed; =20 +/* + * Used by the paravisor only, means that the encrypted ring buffers and + * the encrypted external memory are supported + */ +#define VMBUS_FEATURE_FLAG_CONFIDENTIAL_CHANNELS 0x10 + struct vmbus_channel_initiate_contact { struct vmbus_channel_message_header header; u32 vmbus_version_requested; @@ -630,7 +646,8 @@ struct vmbus_channel_initiate_contact { struct { u8 msg_sint; u8 msg_vtl; - u8 reserved[6]; + u8 reserved[2]; + u32 feature_flags; /* VMBus version 6.0 */ }; }; u64 monitor_page1; @@ -1008,6 +1025,10 @@ struct vmbus_channel { =20 /* boolean to control visibility of sysfs for ring buffer */ bool ring_sysfs_visible; + /* The ring buffer is encrypted */ + bool co_ring_buffer; + /* The external memory is encrypted */ + bool co_external_memory; }; =20 #define lock_requestor(channel, flags) \ @@ -1032,6 +1053,16 @@ u64 vmbus_request_addr_match(struct vmbus_channel *c= hannel, u64 trans_id, u64 rqst_addr); u64 vmbus_request_addr(struct vmbus_channel *channel, u64 trans_id); =20 +static inline bool is_co_ring_buffer(const struct vmbus_channel_offer_chan= nel *o) +{ + return !!(o->offer.chn_flags & VMBUS_CHANNEL_CONFIDENTIAL_RING_BUFFER); +} + +static inline bool is_co_external_memory(const struct vmbus_channel_offer_= channel *o) +{ + return !!(o->offer.chn_flags & VMBUS_CHANNEL_CONFIDENTIAL_EXTERNAL_MEMORY= ); +} + static inline bool is_hvsock_offer(const struct vmbus_channel_offer_channe= l *o) { return !!(o->offer.chn_flags & VMBUS_CHANNEL_TLNPI_PROVIDER_OFFER); --=20 2.43.0