Commit a5ddb745 authored by Michael Kelley's avatar Michael Kelley Committed by Wei Liu
Browse files

Drivers: hv: vmbus: Remove second mapping of VMBus monitor pages 



With changes to how Hyper-V guest VMs flip memory between private
(encrypted) and shared (decrypted), creating a second kernel virtual
mapping for shared memory is no longer necessary.  Everything needed
for the transition to shared is handled by set_memory_decrypted().

As such, remove the code to create and manage the second
mapping for VMBus monitor pages. Because set_memory_decrypted()
and set_memory_encrypted() are no-ops in normal VMs, it's
not even necessary to test for being in a Confidential VM
(a.k.a., "Isolation VM").

Signed-off-by: default avatarMichael Kelley <mikelley@microsoft.com>
Reviewed-by: default avatarTianyu Lan <Tianyu.Lan@microsoft.com>
Link: https://lore.kernel.org/r/1679838727-87310-9-git-send-email-mikelley@microsoft.com


Signed-off-by: default avatarWei Liu <wei.liu@kernel.org>
parent 0459ff48

drivers/hv/connection.c

+28 −85
Original line number Diff line number Diff line
@@ -104,8 +104,14 @@ int vmbus_negotiate_version(struct vmbus_channel_msginfo *msginfo, u32 version) 
		vmbus_connection.msg_conn_id = VMBUS_MESSAGE_CONNECTION_ID;

	}



	msg->monitor_page1 = vmbus_connection.monitor_pages_pa[0];

	msg->monitor_page2 = vmbus_connection.monitor_pages_pa[1];

	/*

	 * shared_gpa_boundary is zero in non-SNP VMs, so it's safe to always

	 * bitwise OR it

	 */

	msg->monitor_page1 = virt_to_phys(vmbus_connection.monitor_pages[0]) |

				ms_hyperv.shared_gpa_boundary;

	msg->monitor_page2 = virt_to_phys(vmbus_connection.monitor_pages[1]) |

				ms_hyperv.shared_gpa_boundary;



	msg->target_vcpu = hv_cpu_number_to_vp_number(VMBUS_CONNECT_CPU);
@@ -219,72 +225,27 @@ int vmbus_connect(void) 
	 * Setup the monitor notification facility. The 1st page for

	 * parent->child and the 2nd page for child->parent

	 */

	vmbus_connection.monitor_pages[0] = (void *)hv_alloc_hyperv_zeroed_page();

	vmbus_connection.monitor_pages[1] = (void *)hv_alloc_hyperv_zeroed_page();

	vmbus_connection.monitor_pages[0] = (void *)hv_alloc_hyperv_page();

	vmbus_connection.monitor_pages[1] = (void *)hv_alloc_hyperv_page();

	if ((vmbus_connection.monitor_pages[0] == NULL) ||

	    (vmbus_connection.monitor_pages[1] == NULL)) {

		ret = -ENOMEM;

		goto cleanup;

	}



	vmbus_connection.monitor_pages_original[0]

		= vmbus_connection.monitor_pages[0];

	vmbus_connection.monitor_pages_original[1]

		= vmbus_connection.monitor_pages[1];

	vmbus_connection.monitor_pages_pa[0]

		= virt_to_phys(vmbus_connection.monitor_pages[0]);

	vmbus_connection.monitor_pages_pa[1]

		= virt_to_phys(vmbus_connection.monitor_pages[1]);



	if (hv_is_isolation_supported()) {

	ret = set_memory_decrypted((unsigned long)

					   vmbus_connection.monitor_pages[0],

					   1);

				vmbus_connection.monitor_pages[0], 1);

	ret |= set_memory_decrypted((unsigned long)

					    vmbus_connection.monitor_pages[1],

					    1);

				vmbus_connection.monitor_pages[1], 1);

	if (ret)

		goto cleanup;



	/*

		 * Isolation VM with AMD SNP needs to access monitor page via

		 * address space above shared gpa boundary.

		 */

		if (hv_isolation_type_snp()) {

			vmbus_connection.monitor_pages_pa[0] +=

				ms_hyperv.shared_gpa_boundary;

			vmbus_connection.monitor_pages_pa[1] +=

				ms_hyperv.shared_gpa_boundary;



			vmbus_connection.monitor_pages[0]

				= memremap(vmbus_connection.monitor_pages_pa[0],

					   HV_HYP_PAGE_SIZE,

					   MEMREMAP_WB);

			if (!vmbus_connection.monitor_pages[0]) {

				ret = -ENOMEM;

				goto cleanup;

			}



			vmbus_connection.monitor_pages[1]

				= memremap(vmbus_connection.monitor_pages_pa[1],

					   HV_HYP_PAGE_SIZE,

					   MEMREMAP_WB);

			if (!vmbus_connection.monitor_pages[1]) {

				ret = -ENOMEM;

				goto cleanup;

			}

		}



		/*

		 * Set memory host visibility hvcall smears memory

		 * and so zero monitor pages here.

	 * Set_memory_decrypted() will change the memory contents if

	 * decryption occurs, so zero monitor pages here.

	 */

		memset(vmbus_connection.monitor_pages[0], 0x00,

		       HV_HYP_PAGE_SIZE);

		memset(vmbus_connection.monitor_pages[1], 0x00,

		       HV_HYP_PAGE_SIZE);



	}

	memset(vmbus_connection.monitor_pages[0], 0x00, HV_HYP_PAGE_SIZE);

	memset(vmbus_connection.monitor_pages[1], 0x00, HV_HYP_PAGE_SIZE);



	msginfo = kzalloc(sizeof(*msginfo) +

			  sizeof(struct vmbus_channel_initiate_contact),
@@ -376,30 +337,12 @@ void vmbus_disconnect(void) 
		vmbus_connection.int_page = NULL;

	}



	if (hv_is_isolation_supported()) {

		/*

		 * memunmap() checks input address is ioremap address or not

		 * inside. It doesn't unmap any thing in the non-SNP CVM and

		 * so not check CVM type here.

		 */

		memunmap(vmbus_connection.monitor_pages[0]);

		memunmap(vmbus_connection.monitor_pages[1]);



		set_memory_encrypted((unsigned long)

			vmbus_connection.monitor_pages_original[0],

			1);

		set_memory_encrypted((unsigned long)

			vmbus_connection.monitor_pages_original[1],

			1);

	}

	set_memory_encrypted((unsigned long)vmbus_connection.monitor_pages[0], 1);

	set_memory_encrypted((unsigned long)vmbus_connection.monitor_pages[1], 1);



	hv_free_hyperv_page((unsigned long)

		vmbus_connection.monitor_pages_original[0]);

	hv_free_hyperv_page((unsigned long)

		vmbus_connection.monitor_pages_original[1]);

	vmbus_connection.monitor_pages_original[0] =

	hv_free_hyperv_page((unsigned long)vmbus_connection.monitor_pages[0]);

	hv_free_hyperv_page((unsigned long)vmbus_connection.monitor_pages[1]);

	vmbus_connection.monitor_pages[0] = NULL;

	vmbus_connection.monitor_pages_original[1] =

	vmbus_connection.monitor_pages[1] = NULL;

}

drivers/hv/hyperv_vmbus.h

+0 −2
Original line number Diff line number Diff line
@@ -241,8 +241,6 @@ struct vmbus_connection { 
	 * is child->parent notification

	 */

	struct hv_monitor_page *monitor_pages[2];

	void *monitor_pages_original[2];

	phys_addr_t monitor_pages_pa[2];

	struct list_head chn_msg_list;

	spinlock_t channelmsg_lock;