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From: Michael Kelley <mikelley@microsoft.com>
To: hpa@zytor.com, kys@microsoft.com, haiyangz@microsoft.com,
	wei.liu@kernel.org, decui@microsoft.com, luto@kernel.org,
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	x86@kernel.org, linux-kernel@vger.kernel.org,
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	linux-pci@vger.kernel.org, linux-arch@vger.kernel.org,
	iommu@lists.linux.dev
Cc: mikelley@microsoft.com
Subject: [PATCH v6 08/13] Drivers: hv: vmbus: Remove second mapping of VMBus monitor pages
Date: Wed,  8 Mar 2023 18:40:09 -0800	[thread overview]
Message-ID: <1678329614-3482-9-git-send-email-mikelley@microsoft.com> (raw)
In-Reply-To: <1678329614-3482-1-git-send-email-mikelley@microsoft.com>

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: Michael Kelley <mikelley@microsoft.com>
Reviewed-by: Tianyu Lan <Tianyu.Lan@microsoft.com>
---
 drivers/hv/connection.c   | 113 ++++++++++++----------------------------------
 drivers/hv/hyperv_vmbus.h |   2 -
 2 files changed, 28 insertions(+), 87 deletions(-)

diff --git a/drivers/hv/connection.c b/drivers/hv/connection.c
index da51b50..5978e9d 100644
--- a/drivers/hv/connection.c
+++ b/drivers/hv/connection.c
@@ -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);
-		ret |= set_memory_decrypted((unsigned long)
-					    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.
-		 */
-		memset(vmbus_connection.monitor_pages[0], 0x00,
-		       HV_HYP_PAGE_SIZE);
-		memset(vmbus_connection.monitor_pages[1], 0x00,
-		       HV_HYP_PAGE_SIZE);
+	ret = set_memory_decrypted((unsigned long)
+				vmbus_connection.monitor_pages[0], 1);
+	ret |= set_memory_decrypted((unsigned long)
+				vmbus_connection.monitor_pages[1], 1);
+	if (ret)
+		goto cleanup;
 
-	}
+	/*
+	 * 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);
 
 	msginfo = kzalloc(sizeof(*msginfo) +
 			  sizeof(struct vmbus_channel_initiate_contact),
@@ -376,31 +337,13 @@ 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] =
-		vmbus_connection.monitor_pages[0] = NULL;
-	vmbus_connection.monitor_pages_original[1] =
-		vmbus_connection.monitor_pages[1] = NULL;
+	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[1] = NULL;
 }
 
 /*
diff --git a/drivers/hv/hyperv_vmbus.h b/drivers/hv/hyperv_vmbus.h
index dc673ed..167ac51 100644
--- a/drivers/hv/hyperv_vmbus.h
+++ b/drivers/hv/hyperv_vmbus.h
@@ -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;
 
-- 
1.8.3.1


  parent reply	other threads:[~2023-03-09  2:45 UTC|newest]

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-03-09  2:40 [PATCH v6 00/13] Add PCI pass-thru support to Hyper-V Confidential VMs Michael Kelley
2023-03-09  2:40 ` [PATCH v6 01/13] x86/ioremap: Add hypervisor callback for private MMIO mapping in coco VM Michael Kelley
2023-03-27 20:09   ` [tip: x86/sev] " tip-bot2 for Michael Kelley
2023-03-09  2:40 ` [PATCH v6 02/13] x86/hyperv: Reorder code to facilitate future work Michael Kelley
2023-03-09  2:40 ` [PATCH v6 03/13] Drivers: hv: Explicitly request decrypted in vmap_pfn() calls Michael Kelley
2023-03-09  2:40 ` [PATCH v6 04/13] x86/mm: Handle decryption/re-encryption of bss_decrypted consistently Michael Kelley
2023-03-27 20:09   ` [tip: x86/sev] " tip-bot2 for Michael Kelley
2023-03-09  2:40 ` [PATCH v6 05/13] init: Call mem_encrypt_init() after Hyper-V hypercall init is done Michael Kelley
2023-03-27 20:09   ` [tip: x86/sev] " tip-bot2 for Michael Kelley
2023-03-09  2:40 ` [PATCH v6 06/13] x86/hyperv: Change vTOM handling to use standard coco mechanisms Michael Kelley
2023-03-20 11:22   ` Borislav Petkov
2023-03-20 13:30     ` Michael Kelley (LINUX)
2023-03-20 18:16       ` Borislav Petkov
2023-03-20 18:50         ` Michael Kelley (LINUX)
2023-03-23 13:43           ` Borislav Petkov
2023-03-24 15:48             ` Borislav Petkov
2023-03-24 17:10               ` Dexuan Cui
2023-03-24 17:28                 ` Sathyanarayanan Kuppuswamy
2023-03-24 18:30                 ` Borislav Petkov
2023-03-24 19:36               ` Michael Kelley (LINUX)
2023-03-25  0:04                 ` Michael Kelley (LINUX)
2023-03-09  2:40 ` [PATCH v6 07/13] swiotlb: Remove bounce buffer remapping for Hyper-V Michael Kelley
2023-03-09  2:40 ` Michael Kelley [this message]
2023-03-09  2:40 ` [PATCH v6 09/13] Drivers: hv: vmbus: Remove second way of mapping ring buffers Michael Kelley
2023-03-09  2:40 ` [PATCH v6 10/13] hv_netvsc: Remove second mapping of send and recv buffers Michael Kelley
2023-03-09  2:40 ` [PATCH v6 11/13] Drivers: hv: Don't remap addresses that are above shared_gpa_boundary Michael Kelley
2023-03-09  2:40 ` [PATCH v6 12/13] PCI: hv: Add hypercalls to read/write MMIO space Michael Kelley
2023-03-24 14:48   ` Lorenzo Pieralisi
2023-03-24 15:13     ` Michael Kelley (LINUX)
2023-03-24 15:24       ` Lorenzo Pieralisi
2023-03-09  2:40 ` [PATCH v6 13/13] PCI: hv: Enable PCI pass-thru devices in Confidential VMs Michael Kelley
2023-03-20 11:27 ` [PATCH v6 00/13] Add PCI pass-thru support to Hyper-V " Borislav Petkov

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