Merge tag 'for-linus-6.16-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip

Pull xen updates from Juergen Gross:

 - A fix for running as a Xen dom0 on the iMX8QXP Arm platform

 - An update of the xen.config adding XEN_UNPOPULATED_ALLOC for better
   support of PVH dom0

 - A fix of the Xen balloon driver when running without
   CONFIG_XEN_UNPOPULATED_ALLOC

 - A fix of the dm_op Xen hypercall on Arm needed to pass user space
   buffers to the hypervisor in certain configurations

* tag 'for-linus-6.16-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
  xen/arm: call uaccess_ttbr0_enable for dm_op hypercall
  xen/x86: fix initial memory balloon target
  xen: enable XEN_UNPOPULATED_ALLOC as part of xen.config
  xen: swiotlb: Wire up map_resource callback

Author: torvalds

arch/arm64/xen/hypercall.S

@@ -83,7 +83,26 @@ HYPERCALL3(vcpu_op);
 HYPERCALL1(platform_op_raw);
 HYPERCALL2(multicall);
 HYPERCALL2(vm_assist);
-HYPERCALL3(dm_op);
+
+SYM_FUNC_START(HYPERVISOR_dm_op)
+	mov x16, #__HYPERVISOR_dm_op;	\
+	/*
+	 * dm_op hypercalls are issued by the userspace. The kernel needs to
+	 * enable access to TTBR0_EL1 as the hypervisor would issue stage 1
+	 * translations to user memory via AT instructions. Since AT
+	 * instructions are not affected by the PAN bit (ARMv8.1), we only
+	 * need the explicit uaccess_enable/disable if the TTBR0 PAN emulation
+	 * is enabled (it implies that hardware UAO and PAN disabled).
+	 */
+	uaccess_ttbr0_enable x6, x7, x8
+	hvc XEN_IMM
+
+	/*
+	 * Disable userspace access from kernel once the hyp call completed.
+	 */
+	uaccess_ttbr0_disable x6, x7
+	ret
+SYM_FUNC_END(HYPERVISOR_dm_op);
 
 SYM_FUNC_START(privcmd_call)
 	mov x16, x0

drivers/xen/balloon.c

@@ -704,15 +704,18 @@ static int __init balloon_add_regions(void)
 
 		/*
 		 * Extra regions are accounted for in the physmap, but need
-		 * decreasing from current_pages to balloon down the initial
-		 * allocation, because they are already accounted for in
-		 * total_pages.
+		 * decreasing from current_pages and target_pages to balloon
+		 * down the initial allocation, because they are already
+		 * accounted for in total_pages.
 		 */
-		if (extra_pfn_end - start_pfn >= balloon_stats.current_pages) {
+		pages = extra_pfn_end - start_pfn;
+		if (pages >= balloon_stats.current_pages ||
+		    pages >= balloon_stats.target_pages) {
 			WARN(1, "Extra pages underflow current target");
 			return -ERANGE;
 		}
-		balloon_stats.current_pages -= extra_pfn_end - start_pfn;
+		balloon_stats.current_pages -= pages;
+		balloon_stats.target_pages -= pages;
 	}
 
 	return 0;

drivers/xen/swiotlb-xen.c

@@ -426,4 +426,5 @@ const struct dma_map_ops xen_swiotlb_dma_ops = {
 	.alloc_pages_op = dma_common_alloc_pages,
 	.free_pages = dma_common_free_pages,
 	.max_mapping_size = swiotlb_max_mapping_size,
+	.map_resource = dma_direct_map_resource,
 };

kernel/configs/xen.config

@@ -13,6 +13,8 @@ CONFIG_SCSI=y
 CONFIG_FB=y
 CONFIG_INPUT_MISC=y
 CONFIG_MEMORY_HOTPLUG=y
+CONFIG_MEMORY_HOTREMOVE=y
+CONFIG_ZONE_DEVICE=y
 CONFIG_TTY=y
 # Technically not required but otherwise produces
 # pretty useless systems starting from allnoconfig
@@ -47,3 +49,4 @@ CONFIG_XEN_GNTDEV=m
 CONFIG_XEN_GRANT_DEV_ALLOC=m
 CONFIG_SWIOTLB_XEN=y
 CONFIG_XEN_PRIVCMD=m
+CONFIG_XEN_UNPOPULATED_ALLOC=y