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Message-ID: <4B14C8C8.9020604@kernel.org>
Date: Mon, 30 Nov 2009 23:42:00 -0800
From: Yinghai Lu <yinghai@...nel.org>
To: FUJITA Tomonori <fujita.tomonori@....ntt.co.jp>
CC: mingo@...e.hu, linux-kernel@...r.kernel.org
Subject: Re: [PATCH -tip] x86: fix iommu=soft boot option
FUJITA Tomonori wrote:
> On Thu, 26 Nov 2009 23:45:33 -0800
> Yinghai Lu <yinghai@...nel.org> wrote:
>
>>>> when AMD64 mem > 4g, no AGP, BIOS set all gart iommu on all nodes size to 32M, and enable bit are set.
>>> I have such machine (with sane BIOS).
>>>
>>> But if BIOS is broken, early_gart_iommu_check() disables GART_EN bit
>>> (bits 0)?
>> not for 32M small size.
>>
>> that function only clear that bit when different nodes have different setting.
>>
>>>> 1. iommu=soft, will go through POINT A and POINT B
>>> Not always. if aperture_valid() is true, it doesn't go POINT A. My
>>> GART machine doesn't go.
>> maybe your bios set GART iommu set to 64M?
>
> Yeah, my machine has sane BIOS.
>
>
>>>> 2. no "iommu=soft", will go through POINT A and POINT C
>>> As I said, it's not true about POINT A.
>> maybe your bios set GART iommu set to 64M?
>>
>>>
>>>> and all will reach POINT X to make sure ENABLE bit is not set.
>>> POINT X doesn't look make sure ENABLE bit is not set. It just fixes up
>>> (sets) the address and its size.
>> write_pci_config(bus, slot, 3, AMD64_GARTAPERTURECTL, aper_order << 1);
>>
>> that bit is that bit 0 of AMD64_GARTAPERTURECTL reg.
>
> Oops, thanks.
>
> But as I wrote in the previous mail, can you tell me why we need this?
> With 2.6.31 my machine uses swiotlb with GART_EN bit enabled.
>
> My another question is that why can't early_gart_iommu_check()
> _always_ disable GART_EN bit?
please check
[PATCH] x86: fix gart iommu using for amd 64 bit system -v4
after
|commit 75f1cdf1dda92cae037ec848ae63690d91913eac
|Author: FUJITA Tomonori <fujita.tomonori@....ntt.co.jp>
|Date: Tue Nov 10 19:46:20 2009 +0900
|
| x86: Handle HW IOMMU initialization failure gracefully
|
| If HW IOMMU initialization fails (Intel VT-d often does this,
| typically due to BIOS bugs), we fall back to nommu. It doesn't
| work for the majority since nowadays we have more than 4GB
| memory so we must use swiotlb instead of nommu.
...
amd 64 systems that
1. do not have AGP
2. do not have IOMMU
3. mem > 4g
4. BIOS do not allocate correct gart in NB.
will leave them to use SWIOTLB forcely.
also in pci_iommu_alloc()
pci_swiotlb_init is stealing the preallocate range that is for
gart_iommu_hole workaround.
so restore the sequence...
will get back
[ 0.000000] Your BIOS doesn't leave a aperture memory hole
[ 0.000000] Please enable the IOMMU option in the BIOS setup
[ 0.000000] This costs you 64 MB of RAM
[ 0.000000] Mapping aperture over 65536 KB of RAM @ 20000000
...
[ 12.702822] calling pci_iommu_init+0x0/0x31 @ 1
[ 12.708728] PCI-DMA: Disabling AGP.
[ 12.712812] PCI-DMA: aperture base @ 20000000 size 65536 KB
[ 12.718384] PCI-DMA: using GART IOMMU.
[ 12.722139] PCI-DMA: Reserving 64MB of IOMMU area in the AGP aperture
[ 12.736944] initcall pci_iommu_init+0x0/0x31 returned 0 after 28802 usecs
-v2: call shutdown when no agp is there
-v3: add check_store to restore state for swiotlb
separate pci_swiotlb_detect and pci_swiotlb_init from FUJITA
-v4: disable translating in early_gart_iommu_check according to FUJITA
Signed-off-by: Yinghai Lu <yinghai@...nel.org>
---
arch/x86/include/asm/swiotlb.h | 8 ++++++--
arch/x86/kernel/aperture_64.c | 11 ++++++-----
arch/x86/kernel/pci-dma.c | 8 ++++++--
arch/x86/kernel/pci-gart_64.c | 3 ++-
arch/x86/kernel/pci-swiotlb.c | 11 +++++++----
5 files changed, 27 insertions(+), 14 deletions(-)
Index: linux-2.6/arch/x86/kernel/aperture_64.c
===================================================================
--- linux-2.6.orig/arch/x86/kernel/aperture_64.c
+++ linux-2.6/arch/x86/kernel/aperture_64.c
@@ -280,7 +280,8 @@ void __init early_gart_iommu_check(void)
* or BIOS forget to put that in reserved.
* try to update e820 to make that region as reserved.
*/
- int i, fix, slot;
+ u32 agp_aper_base = 0, agp_aper_order = 0;
+ int i, fix, slot, valid_agp = 0;
u32 ctl;
u32 aper_size = 0, aper_order = 0, last_aper_order = 0;
u64 aper_base = 0, last_aper_base = 0;
@@ -290,6 +291,8 @@ void __init early_gart_iommu_check(void)
return;
/* This is mostly duplicate of iommu_hole_init */
+ agp_aper_base = search_agp_bridge(&agp_aper_order, &valid_agp);
+
fix = 0;
for (i = 0; i < ARRAY_SIZE(bus_dev_ranges); i++) {
int bus;
@@ -342,10 +345,10 @@ void __init early_gart_iommu_check(void)
}
}
- if (!fix)
+ if (valid_agp)
return;
- /* different nodes have different setting, disable them all at first*/
+ /* disable them all at first */
for (i = 0; i < ARRAY_SIZE(bus_dev_ranges); i++) {
int bus;
int dev_base, dev_limit;
@@ -458,8 +461,6 @@ out:
if (aper_alloc) {
/* Got the aperture from the AGP bridge */
- } else if (!valid_agp) {
- /* Do nothing */
} else if ((!no_iommu && max_pfn > MAX_DMA32_PFN) ||
force_iommu ||
valid_agp ||
Index: linux-2.6/arch/x86/kernel/pci-dma.c
===================================================================
--- linux-2.6.orig/arch/x86/kernel/pci-dma.c
+++ linux-2.6/arch/x86/kernel/pci-dma.c
@@ -124,8 +124,9 @@ void __init pci_iommu_alloc(void)
/* free the range so iommu could get some range less than 4G */
dma32_free_bootmem();
#endif
- if (pci_swiotlb_init())
- return;
+
+ if (pci_swiotlb_detect())
+ goto out;
gart_iommu_hole_init();
@@ -135,6 +136,9 @@ void __init pci_iommu_alloc(void)
/* needs to be called after gart_iommu_hole_init */
amd_iommu_detect();
+
+out:
+ pci_swiotlb_init();
}
void *dma_generic_alloc_coherent(struct device *dev, size_t size,
Index: linux-2.6/arch/x86/kernel/pci-gart_64.c
===================================================================
--- linux-2.6.orig/arch/x86/kernel/pci-gart_64.c
+++ linux-2.6/arch/x86/kernel/pci-gart_64.c
@@ -710,7 +710,8 @@ static void gart_iommu_shutdown(void)
struct pci_dev *dev;
int i;
- if (no_agp)
+ /* don't shutdown it if there is AGP installed */
+ if (!no_agp)
return;
for (i = 0; i < num_k8_northbridges; i++) {
Index: linux-2.6/arch/x86/include/asm/swiotlb.h
===================================================================
--- linux-2.6.orig/arch/x86/include/asm/swiotlb.h
+++ linux-2.6/arch/x86/include/asm/swiotlb.h
@@ -5,13 +5,17 @@
#ifdef CONFIG_SWIOTLB
extern int swiotlb;
-extern int pci_swiotlb_init(void);
+int pci_swiotlb_detect(void);
+void pci_swiotlb_init(void);
#else
#define swiotlb 0
-static inline int pci_swiotlb_init(void)
+static inline int pci_swiotlb_detect(void)
{
return 0;
}
+static inline void pci_swiotlb_init(void)
+{
+}
#endif
static inline void dma_mark_clean(void *addr, size_t size) {}
Index: linux-2.6/arch/x86/kernel/pci-swiotlb.c
===================================================================
--- linux-2.6.orig/arch/x86/kernel/pci-swiotlb.c
+++ linux-2.6/arch/x86/kernel/pci-swiotlb.c
@@ -43,12 +43,12 @@ static struct dma_map_ops swiotlb_dma_op
};
/*
- * pci_swiotlb_init - initialize swiotlb if necessary
+ * pci_swiotlb_detect - initialize swiotlb if necessary
*
* This returns non-zero if we are forced to use swiotlb (by the boot
* option).
*/
-int __init pci_swiotlb_init(void)
+int __init pci_swiotlb_detect(void)
{
int use_swiotlb = swiotlb | swiotlb_force;
@@ -60,10 +60,13 @@ int __init pci_swiotlb_init(void)
if (swiotlb_force)
swiotlb = 1;
+ return use_swiotlb;
+}
+
+void __init pci_swiotlb_init(void)
+{
if (swiotlb) {
swiotlb_init(0);
dma_ops = &swiotlb_dma_ops;
}
-
- return use_swiotlb;
}
--
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