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authorTom Lendacky <thomas.lendacky@amd.com>2017-10-20 09:30:52 -0500
committerThomas Gleixner <tglx@linutronix.de>2017-11-07 15:35:58 +0100
commit0e4c12b45aa88e74fdda117896d2b61c4e510cb9 (patch)
tree9007109ad9055fd3b23d6ba2d1f0b63e8421337e
parent1d2e733b13b450e5854f4a8f8efcd77fa7362d62 (diff)
downloadlinux-0e4c12b45aa88e74fdda117896d2b61c4e510cb9.tar.bz2
x86/mm, resource: Use PAGE_KERNEL protection for ioremap of memory pages
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
-rw-r--r--arch/x86/mm/ioremap.c79
-rw-r--r--include/linux/ioport.h3
-rw-r--r--kernel/resource.c19
3 files changed, 89 insertions, 12 deletions
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:
diff --git a/include/linux/ioport.h b/include/linux/ioport.h
index c0070d7c4b99..93b4183cf53d 100644
--- a/include/linux/ioport.h
+++ b/include/linux/ioport.h
@@ -271,6 +271,9 @@ extern int
walk_system_ram_range(unsigned long start_pfn, unsigned long nr_pages,
void *arg, int (*func)(unsigned long, unsigned long, void *));
extern int
+walk_mem_res(u64 start, u64 end, void *arg,
+ int (*func)(struct resource *, void *));
+extern int
walk_system_ram_res(u64 start, u64 end, void *arg,
int (*func)(struct resource *, void *));
extern int
diff --git a/kernel/resource.c b/kernel/resource.c
index 8430042fa77b..54ba6de3757c 100644
--- a/kernel/resource.c
+++ b/kernel/resource.c
@@ -397,6 +397,8 @@ static int find_next_iomem_res(struct resource *res, unsigned long desc,
res->start = p->start;
if (res->end > p->end)
res->end = p->end;
+ res->flags = p->flags;
+ res->desc = p->desc;
return 0;
}
@@ -467,6 +469,23 @@ int walk_system_ram_res(u64 start, u64 end, void *arg,
arg, func);
}
+/*
+ * This function calls the @func callback against all memory ranges, which
+ * are ranges marked as IORESOURCE_MEM and IORESOUCE_BUSY.
+ */
+int walk_mem_res(u64 start, u64 end, void *arg,
+ int (*func)(struct resource *, void *))
+{
+ struct resource res;
+
+ res.start = start;
+ res.end = end;
+ res.flags = IORESOURCE_MEM | IORESOURCE_BUSY;
+
+ return __walk_iomem_res_desc(&res, IORES_DESC_NONE, true,
+ arg, func);
+}
+
#if !defined(CONFIG_ARCH_HAS_WALK_MEMORY)
/*