Re: [PATCH hyperv-next v2 2/4] drivers: hyperv: VMBus protocol version 6.0

[ALOK TIWARI <alok.a.tiwari@oracle.com>]

On 12-05-2025 04:37, Roman Kisel wrote:
> The confidential VMBus is supported starting from the protocol
> version 6.0 onwards.
> 
> Update the relevant definitions, provide a function that returns
> whether VMBus is condifential or not.

typo condifential -> confidential

> 
> Signed-off-by: Roman Kisel <romank@linux.microsoft.com>
> ---
>   drivers/hv/vmbus_drv.c         | 12 ++++++
>   include/asm-generic/mshyperv.h |  1 +
>   include/linux/hyperv.h         | 71 +++++++++++++++++++++++++---------
>   3 files changed, 65 insertions(+), 19 deletions(-)
> 
> diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
> index 1d5c9dcf712e..e431978fa408 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 6c51a25ed7b5..96e0723d0720 100644
> --- a/include/asm-generic/mshyperv.h
> +++ b/include/asm-generic/mshyperv.h
> @@ -377,6 +377,7 @@ 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 1f310fbbc4f9..3cf48f29e6b4 100644
> --- a/include/linux/hyperv.h
> +++ b/include/linux/hyperv.h
> @@ -265,16 +265,19 @@ 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_WIN_IRON				VERSION_WIN10_V5_3
> +#define VERSION_WIN_COPPER				VMBUS_MAKE_VERSION(6, 0)
>   
>   /* Make maximum size of pipe payload of 16K */
>   #define MAX_PIPE_DATA_PAYLOAD		(sizeof(u8) * 16384)
> @@ -335,14 +338,22 @@ 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 +632,12 @@ 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

Clearly convey the purpose of the flag, similar to the previous one
For example ->"Indicates support for encrypted ring buffers and external 
memory, used exclusively by the paravisor."

> + */
> +#define VMBUS_FEATURE_FLAG_CONFIDENTIAL_CHANNELS	0x10
> +
>   struct vmbus_channel_initiate_contact {
>   	struct vmbus_channel_message_header header;
>   	u32 vmbus_version_requested;
> @@ -630,7 +647,8 @@ 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;
> @@ -1002,6 +1020,11 @@ struct vmbus_channel {
>   
>   	/* The max size of a packet on this channel */
>   	u32 max_pkt_size;
> +
> +	/* The ring buffer is encrypted */
> +	bool confidential_ring_buffer;
> +	/* The external memory is encrypted */
> +	bool confidential_external_memory;
>   };
>   

Thanks,
Alok