From 0e4c12b45aa88e74fdda117896d2b61c4e510cb9 Mon Sep 17 00:00:00 2001
From: Tom Lendacky <thomas.lendacky@amd.com>
Date: Fri, 20 Oct 2017 09:30:52 -0500
Subject: x86/mm, resource: Use PAGE_KERNEL protection for ioremap of memory
pages
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In order for memory pages to be properly mapped when SEV is active, it's
necessary to use the PAGE_KERNEL protection attribute as the base
protection. This ensures that memory mapping of, e.g. ACPI tables,
receives the proper mapping attributes.
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Borislav Petkov <bp@suse.de>
Tested-by: Borislav Petkov <bp@suse.de>
Cc: Laura Abbott <labbott@redhat.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: kvm@vger.kernel.org
Cc: Jérôme Glisse <jglisse@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Link: https://lkml.kernel.org/r/20171020143059.3291-11-brijesh.singh@amd.com
---
arch/x86/mm/ioremap.c | 79 +++++++++++++++++++++++++++++++++++++++++++--------
1 file changed, 67 insertions(+), 12 deletions(-)
(limited to 'arch/x86')
diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c
index 52cc0f4ed494..6e4573b1da34 100644
--- a/arch/x86/mm/ioremap.c
+++ b/arch/x86/mm/ioremap.c
@@ -27,6 +27,11 @@
#include "physaddr.h"
+struct ioremap_mem_flags {
+ bool system_ram;
+ bool desc_other;
+};
+
/*
* Fix up the linear direct mapping of the kernel to avoid cache attribute
* conflicts.
@@ -56,17 +61,59 @@ int ioremap_change_attr(unsigned long vaddr, unsigned long size,
return err;
}
-static int __ioremap_check_ram(unsigned long start_pfn, unsigned long nr_pages,
- void *arg)
+static bool __ioremap_check_ram(struct resource *res)
{
+ unsigned long start_pfn, stop_pfn;
unsigned long i;
- for (i = 0; i < nr_pages; ++i)
- if (pfn_valid(start_pfn + i) &&
- !PageReserved(pfn_to_page(start_pfn + i)))
- return 1;
+ if ((res->flags & IORESOURCE_SYSTEM_RAM) != IORESOURCE_SYSTEM_RAM)
+ return false;
- return 0;
+ start_pfn = (res->start + PAGE_SIZE - 1) >> PAGE_SHIFT;
+ stop_pfn = (res->end + 1) >> PAGE_SHIFT;
+ if (stop_pfn > start_pfn) {
+ for (i = 0; i < (stop_pfn - start_pfn); ++i)
+ if (pfn_valid(start_pfn + i) &&
+ !PageReserved(pfn_to_page(start_pfn + i)))
+ return true;
+ }
+
+ return false;
+}
+
+static int __ioremap_check_desc_other(struct resource *res)
+{
+ return (res->desc != IORES_DESC_NONE);
+}
+
+static int __ioremap_res_check(struct resource *res, void *arg)
+{
+ struct ioremap_mem_flags *flags = arg;
+
+ if (!flags->system_ram)
+ flags->system_ram = __ioremap_check_ram(res);
+
+ if (!flags->desc_other)
+ flags->desc_other = __ioremap_check_desc_other(res);
+
+ return flags->system_ram && flags->desc_other;
+}
+
+/*
+ * To avoid multiple resource walks, this function walks resources marked as
+ * IORESOURCE_MEM and IORESOURCE_BUSY and looking for system RAM and/or a
+ * resource described not as IORES_DESC_NONE (e.g. IORES_DESC_ACPI_TABLES).
+ */
+static void __ioremap_check_mem(resource_size_t addr, unsigned long size,
+ struct ioremap_mem_flags *flags)
+{
+ u64 start, end;
+
+ start = (u64)addr;
+ end = start + size - 1;
+ memset(flags, 0, sizeof(*flags));
+
+ walk_mem_res(start, end, flags, __ioremap_res_check);
}
/*
@@ -87,9 +134,10 @@ static void __iomem *__ioremap_caller(resource_size_t phys_addr,
unsigned long size, enum page_cache_mode pcm, void *caller)
{
unsigned long offset, vaddr;
- resource_size_t pfn, last_pfn, last_addr;
+ resource_size_t last_addr;
const resource_size_t unaligned_phys_addr = phys_addr;
const unsigned long unaligned_size = size;
+ struct ioremap_mem_flags mem_flags;
struct vm_struct *area;
enum page_cache_mode new_pcm;
pgprot_t prot;
@@ -108,13 +156,12 @@ static void __iomem *__ioremap_caller(resource_size_t phys_addr,
return NULL;
}
+ __ioremap_check_mem(phys_addr, size, &mem_flags);
+
/*
* Don't allow anybody to remap normal RAM that we're using..
*/
- pfn = phys_addr >> PAGE_SHIFT;
- last_pfn = last_addr >> PAGE_SHIFT;
- if (walk_system_ram_range(pfn, last_pfn - pfn + 1, NULL,
- __ioremap_check_ram) == 1) {
+ if (mem_flags.system_ram) {
WARN_ONCE(1, "ioremap on RAM at %pa - %pa\n",
&phys_addr, &last_addr);
return NULL;
@@ -146,7 +193,15 @@ static void __iomem *__ioremap_caller(resource_size_t phys_addr,
pcm = new_pcm;
}
+ /*
+ * If the page being mapped is in memory and SEV is active then
+ * make sure the memory encryption attribute is enabled in the
+ * resulting mapping.
+ */
prot = PAGE_KERNEL_IO;
+ if (sev_active() && mem_flags.desc_other)
+ prot = pgprot_encrypted(prot);
+
switch (pcm) {
case _PAGE_CACHE_MODE_UC:
default:
--
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