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Date: Thu, 18 Apr 2019 12:01:38 +0200
From: Borislav Petkov <bp@...en8.de>
To: lijiang <lijiang@...hat.com>
Cc: Thomas.Lendacky@....com, linux-kernel@...r.kernel.org,
kexec@...ts.infradead.org, tglx@...utronix.de, mingo@...hat.com,
akpm@...ux-foundation.org, dave.hansen@...ux.intel.com,
luto@...nel.org, peterz@...radead.org, x86@...nel.org,
hpa@...or.com, dyoung@...hat.com, bhe@...hat.com
Subject: Re: [PATCH 1/2 RESEND v10] x86/mm, resource: add a new I/O resource
descriptor 'IORES_DESC_RESERVED'
On Wed, Apr 17, 2019 at 02:40:09PM +0800, lijiang wrote:
> Based on the above description, i made a draft patch, please refer to it. But it
> seems that the code has been changed a lot.
It goes in the right direction. Here is a version where I corrected some
things:
---
diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c
index dd73d5d74393..0c1392e76b7d 100644
--- a/arch/x86/mm/ioremap.c
+++ b/arch/x86/mm/ioremap.c
@@ -27,9 +27,8 @@
#include "physaddr.h"
-struct ioremap_mem_flags {
- bool system_ram;
- bool desc_other;
+struct ioremap_desc {
+ u64 flags;
};
/*
@@ -61,13 +60,13 @@ int ioremap_change_attr(unsigned long vaddr, unsigned long size,
return err;
}
-static bool __ioremap_check_ram(struct resource *res)
+static u64 __ioremap_check_ram(struct resource *res)
{
unsigned long start_pfn, stop_pfn;
unsigned long i;
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;
@@ -75,28 +74,39 @@ static bool __ioremap_check_ram(struct resource *res)
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 IORES_MAP_SYSTEM_RAM;
}
- return false;
+ return 0;
}
-static int __ioremap_check_desc_other(struct resource *res)
+/*
+ * NONE and RESERVED should not be mapped encrypted in SEV because there
+ * the whole memory is already encrypted.
+ */
+static unsigned long __ioremap_check_desc(struct resource *res)
{
- return (res->desc != IORES_DESC_NONE);
+ if (!sev_active())
+ return 0;
+
+ if (res->desc & (IORES_DESC_NONE | IORES_DESC_RESERVED))
+ return 0;
+
+ return IORES_MAP_ENCRYPTED;
}
static int __ioremap_res_check(struct resource *res, void *arg)
{
- struct ioremap_mem_flags *flags = arg;
+ struct ioremap_desc *desc = arg;
- if (!flags->system_ram)
- flags->system_ram = __ioremap_check_ram(res);
+ if (!(desc->flags & IORES_MAP_SYSTEM_RAM))
+ desc->flags |= __ioremap_check_ram(res);
- if (!flags->desc_other)
- flags->desc_other = __ioremap_check_desc_other(res);
+ if (!(desc->flags & IORES_MAP_ENCRYPTED))
+ desc->flags |= __ioremap_check_desc(res);
- return flags->system_ram && flags->desc_other;
+ return ((desc->flags & (IORES_MAP_SYSTEM_RAM | IORES_MAP_ENCRYPTED)) ==
+ (IORES_MAP_SYSTEM_RAM | IORES_MAP_ENCRYPTED));
}
/*
@@ -105,13 +115,13 @@ static int __ioremap_res_check(struct resource *res, void *arg)
* 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)
+ struct ioremap_desc *desc)
{
u64 start, end;
start = (u64)addr;
end = start + size - 1;
- memset(flags, 0, sizeof(*flags));
+ memset(desc, 0, sizeof(struct ioremap_desc));
walk_mem_res(start, end, flags, __ioremap_res_check);
}
@@ -138,7 +148,7 @@ static void __iomem *__ioremap_caller(resource_size_t phys_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 ioremap_desc io_desc;
struct vm_struct *area;
enum page_cache_mode new_pcm;
pgprot_t prot;
@@ -157,12 +167,12 @@ static void __iomem *__ioremap_caller(resource_size_t phys_addr,
return NULL;
}
- __ioremap_check_mem(phys_addr, size, &mem_flags);
+ __ioremap_check_mem(phys_addr, size, &io_desc);
/*
* Don't allow anybody to remap normal RAM that we're using..
*/
- if (mem_flags.system_ram) {
+ if (io_desc.flags & IORES_MAP_SYSTEM_RAM) {
WARN_ONCE(1, "ioremap on RAM at %pa - %pa\n",
&phys_addr, &last_addr);
return NULL;
@@ -200,7 +210,7 @@ static void __iomem *__ioremap_caller(resource_size_t phys_addr,
* resulting mapping.
*/
prot = PAGE_KERNEL_IO;
- if ((sev_active() && mem_flags.desc_other) || encrypted)
+ if ((io_desc.flags & IORES_MAP_ENCRYPTED) || encrypted)
prot = pgprot_encrypted(prot);
switch (pcm) {
diff --git a/include/linux/ioport.h b/include/linux/ioport.h
index da0ebaec25f0..2a5e0f1ded93 100644
--- a/include/linux/ioport.h
+++ b/include/linux/ioport.h
@@ -12,6 +12,7 @@
#ifndef __ASSEMBLY__
#include <linux/compiler.h>
#include <linux/types.h>
+#include <linux/bits.h>
/*
* Resources are tree-like, allowing
* nesting etc..
@@ -135,6 +136,14 @@ enum {
IORES_DESC_DEVICE_PUBLIC_MEMORY = 7,
};
+/*
+ * Flags controlling ioremap() behavior.
+ */
+enum {
+ IORES_MAP_SYSTEM_RAM = BIT(0),
+ IORES_MAP_ENCRYPTED = BIT(1),
+};
+
/* helpers to define resources */
#define DEFINE_RES_NAMED(_start, _size, _name, _flags) \
{ \
--
Regards/Gruss,
Boris.
Good mailing practices for 400: avoid top-posting and trim the reply.
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