From 1f32b0291e98217d6a802e0ee30acb1a4929f84a Mon Sep 17 00:00:00 2001 From: =?utf8?q?Roger=20Pau=20Monn=C3=A9?= Date: Fri, 10 Feb 2017 10:40:29 +0100 Subject: [PATCH] x86/acpi: fix unmapping of low 1MB memory in acpi_os_unmap_memory MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit Current code in acpi_os_map_memory uses the direct map in order to map memory in the low 1MB, but acpi_os_unmap_memory doesn't takes that into account, and always tries to perform a vunmap, which results in the following WARN: (XEN) Xen WARN at vmap.c:185 (XEN) ----[ Xen-4.9-unstable x86_64 debug=y Tainted: C ]---- (XEN) CPU: 0 (XEN) RIP: e008:[] vmap.c#vm_free+0xd7/0xe0 [...] (XEN) Xen call trace: (XEN) [] vmap.c#vm_free+0xd7/0xe0 (XEN) [] acpi_find_root_pointer+0x3a/0x170 (XEN) [] acpi_os_get_root_pointer+0x4e/0x60 (XEN) [] domain_build.c#pvh_setup_acpi_xsdt+0x90/0x240 (XEN) [] domain_build.c#pvh_setup_acpi+0x18a/0x2e0 (XEN) [] domain_build.c#construct_dom0_pvh+0xd2/0x120 (XEN) [] __start_xen+0x1d14/0x2420 (XEN) [] __high_start+0x53/0x60 Fix this by checking if the virtual address passed to acpi_os_unmap_memory belongs to the direct map. Signed-off-by: Roger Pau Monné Reviewed-by: Jan Beulich --- xen/drivers/acpi/osl.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/xen/drivers/acpi/osl.c b/xen/drivers/acpi/osl.c index 7199047198..930e2d9afb 100644 --- a/xen/drivers/acpi/osl.c +++ b/xen/drivers/acpi/osl.c @@ -104,6 +104,13 @@ acpi_os_map_memory(acpi_physical_address phys, acpi_size size) void acpi_os_unmap_memory(void __iomem * virt, acpi_size size) { + if (IS_ENABLED(CONFIG_X86) && + (unsigned long)virt >= DIRECTMAP_VIRT_START && + (unsigned long)virt < DIRECTMAP_VIRT_END) { + ASSERT(!((__pa(virt) + size - 1) >> 20)); + return; + } + if (system_state >= SYS_STATE_boot) vunmap((void *)((unsigned long)virt & PAGE_MASK)); } -- 2.30.2