From: Roman Kisel <romank@xxxxxxxxxxxxxxxxxxx> Sent: Monday, July 14, 2025 3:16 PM
>
> The confidential VMBus is supported starting from the protocol
> version 6.0 onwards.
>
> Update the relevant definitions, and provide a function that returns
> whether VMBus is confidential or not. No functional changes.
>
> Signed-off-by: Roman Kisel <romank@xxxxxxxxxxxxxxxxxxx>
> Reviewed-by: Alok Tiwari <alok.a.tiwari@xxxxxxxxxx>
Reviewed-by: Michael Kelley <mhklinux@xxxxxxxxxxx>
> ---
> drivers/hv/vmbus_drv.c | 12 ++++++
> include/asm-generic/mshyperv.h | 1 +
> include/linux/hyperv.h | 69 ++++++++++++++++++++++++----------
> 3 files changed, 63 insertions(+), 19 deletions(-)
>
> diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
> index 33b524b4eb5e..698c86c4ef03 100644
> --- a/drivers/hv/vmbus_drv.c
> +++ b/drivers/hv/vmbus_drv.c
> @@ -56,6 +56,18 @@ static long __percpu *vmbus_evt;
> int vmbus_irq;
> int vmbus_interrupt;
>
> +/*
> + * 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 a729b77983fa..9722934a8332 100644
> --- a/include/asm-generic/mshyperv.h
> +++ b/include/asm-generic/mshyperv.h
> @@ -373,6 +373,7 @@ static inline int hv_call_create_vp(int node, u64 partition_id, u32 vp_index, u3
> return -EOPNOTSUPP;
> }
> #endif /* CONFIG_MSHV_ROOT */
> +bool vmbus_is_confidential(void);
>
> #if IS_ENABLED(CONFIG_HYPERV_VTL_MODE)
> u8 __init get_vtl(void);
> 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.
> */
>
> -#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)
>
> /* 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;
>
> /* 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 must
> + * 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 must
> + * 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
>
> struct vmpacket_descriptor {
> u16 type;
> @@ -621,6 +631,12 @@ struct vmbus_channel_relid_released {
> u32 child_relid;
> } __packed;
>
> +/*
> + * 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 {
>
> /* 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;
> };
>
> #define lock_requestor(channel, flags) \
> @@ -1032,6 +1053,16 @@ u64 vmbus_request_addr_match(struct vmbus_channel *channel, u64 trans_id,
> u64 rqst_addr);
> u64 vmbus_request_addr(struct vmbus_channel *channel, u64 trans_id);
>
> +static inline bool is_co_ring_buffer(const struct vmbus_channel_offer_channel *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_channel *o)
> {
> return !!(o->offer.chn_flags & VMBUS_CHANNEL_TLNPI_PROVIDER_OFFER);
> --
> 2.43.0
