Intel HD Audio: sound stops working in Xen PV dom0 in >=5.17
Takashi Iwai
tiwai at suse.de
Fri Jan 20 14:19:08 CET 2023
On Fri, 20 Jan 2023 13:11:34 +0100,
Marek Marczykowski-Górecki wrote:
>
> On Fri, Jan 20, 2023 at 08:26:09AM +0100, Takashi Iwai wrote:
> > On Fri, 20 Jan 2023 03:24:30 +0100,
> > Marek Marczykowski-Górecki wrote:
> > >
> > > On Fri, Jan 20, 2023 at 02:10:37AM +0100, Marek Marczykowski-Górecki wrote:
> > > > On Wed, Jan 18, 2023 at 01:39:56PM +0100, Takashi Iwai wrote:
> > > > > On Wed, 18 Jan 2023 11:39:18 +0100,
> > > > > Marek Marczykowski-Górecki wrote:
> > > > > >
> > > > > > On Wed, Jan 18, 2023 at 09:59:26AM +0100, Takashi Iwai wrote:
> > > > > > > On Tue, 17 Jan 2023 21:34:11 +0100,
> > > > > > > Marek Marczykowski-Górecki wrote:
> > > > > > > >
> > > > > > > > On Tue, Jan 17, 2023 at 05:52:25PM +0100, Takashi Iwai wrote:
> > > > > > > > > On Tue, 17 Jan 2023 17:49:28 +0100,
> > > > > > > > > Marek Marczykowski-Górecki wrote:
> > > > > > > > > >
> > > > > > > > > > On Tue, Jan 17, 2023 at 03:33:42PM +0100, Takashi Iwai wrote:
> > > > > > > > > > > On Tue, 17 Jan 2023 15:21:23 +0100,
> > > > > > > > > > > Marek Marczykowski-Górecki wrote:
> > > > > > > > > > > >
> > > > > > > > > > > > On Tue, Jan 17, 2023 at 12:36:28PM +0100, Marek Marczykowski-Górecki wrote:
> > > > > > > > > > > > > On Tue, Jan 17, 2023 at 08:58:57AM +0100, Takashi Iwai wrote:
> > > > > > > > > > > > > > On Mon, 16 Jan 2023 16:55:11 +0100,
> > > > > > > > > > > > > > Takashi Iwai wrote:
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > On Tue, 27 Dec 2022 16:26:54 +0100,
> > > > > > > > > > > > > > > Marek Marczykowski-Górecki wrote:
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > On Thu, Dec 22, 2022 at 09:09:15AM +0100, Takashi Iwai wrote:
> > > > > > > > > > > > > > > > > On Sat, 10 Dec 2022 17:17:42 +0100,
> > > > > > > > > > > > > > > > > Marek Marczykowski-Górecki wrote:
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > On Sat, Dec 10, 2022 at 02:00:06AM +0100, Marek Marczykowski-Górecki wrote:
> > > > > > > > > > > > > > > > > > > On Fri, Dec 09, 2022 at 01:40:15PM +0100, Marek Marczykowski-Górecki wrote:
> > > > > > > > > > > > > > > > > > > > On Fri, Dec 09, 2022 at 09:10:19AM +0100, Takashi Iwai wrote:
> > > > > > > > > > > > > > > > > > > > > On Fri, 09 Dec 2022 02:27:30 +0100,
> > > > > > > > > > > > > > > > > > > > > Marek Marczykowski-Górecki wrote:
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > > Hi,
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > > Under Xen PV dom0, with Linux >= 5.17, sound stops working after few
> > > > > > > > > > > > > > > > > > > > > > hours. pavucontrol still shows meter bars moving, but the speakers
> > > > > > > > > > > > > > > > > > > > > > remain silent. At least on some occasions I see the following message in
> > > > > > > > > > > > > > > > > > > > > > dmesg:
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > > [ 2142.484553] snd_hda_intel 0000:00:1f.3: Unstable LPIB (18144 >= 6396); disabling LPIB delay counting
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > Hit the issue again, this message did not appear in the log (or at least
> > > > > > > > > > > > > > > > > > > not yet).
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > (...)
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > In anyway, please check the behavior with 6.1-rc8 + the commit
> > > > > > > > > > > > > > > > > > > > > cc26516374065a34e10c9a8bf3e940e42cd96e2a
> > > > > > > > > > > > > > > > > > > > > ALSA: memalloc: Allocate more contiguous pages for fallback case
> > > > > > > > > > > > > > > > > > > > > from for-next of my sound git tree (which will be in 6.2-rc1).
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > This did not helped.
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > Looking at the mentioned commits, there is one specific aspect of Xen PV
> > > > > > > > > > > > > > > > > > > > that may be relevant. It configures PAT differently than native Linux.
> > > > > > > > > > > > > > > > > > > > Theoretically Linux adapts automatically and using proper API (like
> > > > > > > > > > > > > > > > > > > > set_memory_wc()) should just work, but at least for i915 driver it
> > > > > > > > > > > > > > > > > > > > causes issues (not fully tracked down yet). Details about that bug
> > > > > > > > > > > > > > > > > > > > report include some more background:
> > > > > > > > > > > > > > > > > > > > https://lore.kernel.org/intel-gfx/Y5Hst0bCxQDTN7lK@mail-itl/
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > Anyway, I have tested it on a Xen modified to setup PAT the same way as
> > > > > > > > > > > > > > > > > > > > native Linux and the audio issue is still there.
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > If the problem persists, another thing to check is the hack below
> > > > > > > > > > > > > > > > > > > > > works.
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > Trying this one now.
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > And this one didn't either :/
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > (Sorry for the late reply, as I've been off in the last weeks.)
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > I think the hack doesn't influence on the PCM buffer pages, but only
> > > > > > > > > > > > > > > > > about BDL pages. Could you check the patch below instead?
> > > > > > > > > > > > > > > > > It'll disable the SG-buffer handling on x86 completely.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > This seems to "fix" the issue, thanks!
> > > > > > > > > > > > > > > > I guess I'll run it this way for now, but a proper solution would be
> > > > > > > > > > > > > > > > nice. Let me know if I can collect any more info that would help with
> > > > > > > > > > > > > > > > that.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > Then we seem to go back again with the coherent memory allocation for
> > > > > > > > > > > > > > > the fallback sg cases. It was changed because the use of
> > > > > > > > > > > > > > > dma_alloc_coherent() caused a problem with IOMMU case for retrieving
> > > > > > > > > > > > > > > the page addresses, but since the commit 9736a325137b, we essentially
> > > > > > > > > > > > > > > avoid the fallback when IOMMU is used, so it should be fine again.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > Let me know if the patch like below works for you instead of the
> > > > > > > > > > > > > > > previous hack to disable SG-buffer (note: totally untested!)
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > Gah, there was an obvious typo, scratch that.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > Below is a proper patch. Please try this one instead.
> > > > > > > > > > > > >
> > > > > > > > > > > > > Thanks, I'll give it a try.
> > > > > > > > > > > >
> > > > > > > > > > > > Unfortunately, it doesn't help, it stopped working again, after about 3h
> > > > > > > > > > > > uptime.
> > > > > > > > > > >
> > > > > > > > > > > Aha, then it might be rather other way round;
> > > > > > > > > > > dma_alloc_noncontiguous() doesn't work on Xen properly.
> > > > > > > > > > >
> > > > > > > > > > > Could you try the one below instead of the previous?
> > > > > > > > > >
> > > > > > > > > > Unfortunately, this one doesn't fix it either :/
> > > > > > > > >
> > > > > > > > > Hmm. Then how about applying both of the last two patches? The last
> > > > > > > > > one to enforce the fallback allocation and the previous one to use
> > > > > > > > > dma_alloc_coherent(). It should be essentially reverting to the old
> > > > > > > > > way.
> > > > > > > >
> > > > > > > > Oh, I noticed only now: the last patch made it fail to initialize.
> > > > > > >
> > > > > > > The "last patch" means the patch to enforce the fallback allocation?
> > > > > >
> > > > > > Yes, the one about dma_alloc_noncontiguous().
> > > > > >
> > > > > > > > I
> > > > > > > > don't see obvious errors in dmesg, but when trying aplay, I get:
> > > > > > > >
> > > > > > > > ALSA lib pcm_direct.c:1284:(snd1_pcm_direct_initialize_slave) unable to install hw params
> > > > > > > > ALSA lib pcm_dmix.c:1087:(snd_pcm_dmix_open) unable to initialize slave
> > > > > > > > aplay: main:830: audio open error: Cannot allocate memory
> > > > > > >
> > > > > > > It's -ENOMEM, so it must be from there. Does it appear always? If
> > > > > > > yes, your system is with IOMMU, and the patch made return always NULL
> > > > > > > intentionally.
> > > > > >
> > > > > > While the system do have IOMMU, it isn't configured by Linux, but by
> > > > > > Xen. And it maps all the memory that Linux see.
> > > > > >
> > > > > > > If that's the case, the problem is that IOMMU doesn't handle the
> > > > > > > coherent memory on Xen.
> > > > > > >
> > > > > > > Please check more explicitly, whether get_dma_ops(dmab->dev.dev) call
> > > > > > > in snd_dma_noncontig_alloc() returns NULL or not.
> > > > > >
> > > > > > Will do.
> > > > >
> > > > > If get_dma_ops() is non-NULL,
> > > >
> > > > Yes, it's non-NULL.
> > > >
> > > > > it means we need some Xen-specific
> > > > > workaround not to use dma_alloc_noncontiguous().
> > > > > What's the best way to see whether the driver is running on Xen PV?
> > > >
> > > > Usually it's this: cpu_feature_enabled(X86_FEATURE_XENPV)
> > > >
> > > > > Meanwhile, it's helpful if you can try the combo of my last two
> > > > > patches, too. It should work, and if it doesn't, it implies that
> > > > > we're looking at a wrong place.
> > > >
> > > > It doesn't because the last of them causes "Cannot allocate memory".
> > > > I'm trying now with this on top:
> > > >
> > > > ---8<---
> > > > diff --git a/sound/core/memalloc.c b/sound/core/memalloc.c
> > > > index 97d7b8106869..e927d18d1ebb 100644
> > > > --- a/sound/core/memalloc.c
> > > > +++ b/sound/core/memalloc.c
> > > > @@ -545,7 +545,7 @@ static void *snd_dma_noncontig_alloc(struct snd_dma_buffer *dmab, size_t size)
> > > > // sgt = dma_alloc_noncontiguous(dmab->dev.dev, size, dmab->dev.dir,
> > > > // DEFAULT_GFP, 0);
> > > > #ifdef CONFIG_SND_DMA_SGBUF
> > > > - if (!sgt && !get_dma_ops(dmab->dev.dev)) {
> > > > + if (!sgt) { // && !get_dma_ops(dmab->dev.dev)) {
> > > > if (dmab->dev.type == SNDRV_DMA_TYPE_DEV_WC_SG)
> > > > dmab->dev.type = SNDRV_DMA_TYPE_DEV_WC_SG_FALLBACK;
> > > > else
> > > > ---8<---
> > >
> > > Unfortunately, the above doesn't help. I mean, I don't get an error
> > > anymore, but no sound output either (even though pavucontrol says I
> > > should hear it). So, it's like the original issue, but without any
> > > delay, just straight from the start.
> >
> > Hmm, it's the result with the combination of both patches, right?
>
> Yes.
>
> > What I meant as the combo is something like below.
>
> Something like this, yes.
It's puzzling, then. The patch changes the allocation with the
dma_alloc_coherent(), and that's what does with the Kconfig hack
you've tested. One possible significant difference is the use of the
DMA address.
> BTW, xen_domain() will also return true on PVH/HVM domain, which should
> not need any of this special treatment. It's PV that is weird.
OK, then it can be an overkill.
Below is another try: it changes the different use of the DMA buffer
address. Let's cross fingers.
thanks,
Takashi
-- 8< --
--- a/sound/core/memalloc.c
+++ b/sound/core/memalloc.c
@@ -541,10 +541,9 @@ static void *snd_dma_noncontig_alloc(struct snd_dma_buffer *dmab, size_t size)
struct sg_table *sgt;
void *p;
- sgt = dma_alloc_noncontiguous(dmab->dev.dev, size, dmab->dev.dir,
- DEFAULT_GFP, 0);
#ifdef CONFIG_SND_DMA_SGBUF
- if (!sgt && !get_dma_ops(dmab->dev.dev)) {
+ if (cpu_feature_enabled(X86_FEATURE_XENPV) ||
+ !get_dma_ops(dmab->dev.dev)) {
if (dmab->dev.type == SNDRV_DMA_TYPE_DEV_WC_SG)
dmab->dev.type = SNDRV_DMA_TYPE_DEV_WC_SG_FALLBACK;
else
@@ -552,6 +551,8 @@ static void *snd_dma_noncontig_alloc(struct snd_dma_buffer *dmab, size_t size)
return snd_dma_sg_fallback_alloc(dmab, size);
}
#endif
+ sgt = dma_alloc_noncontiguous(dmab->dev.dev, size, dmab->dev.dir,
+ DEFAULT_GFP, 0);
if (!sgt)
return NULL;
@@ -719,17 +720,30 @@ static const struct snd_malloc_ops snd_dma_sg_wc_ops = {
struct snd_dma_sg_fallback {
size_t count;
struct page **pages;
+ dma_addr_t *addrs;
};
static void __snd_dma_sg_fallback_free(struct snd_dma_buffer *dmab,
struct snd_dma_sg_fallback *sgbuf)
{
- bool wc = dmab->dev.type == SNDRV_DMA_TYPE_DEV_WC_SG_FALLBACK;
- size_t i;
-
- for (i = 0; i < sgbuf->count && sgbuf->pages[i]; i++)
- do_free_pages(page_address(sgbuf->pages[i]), PAGE_SIZE, wc);
+ size_t i, size;
+
+ if (sgbuf->pages && sgbuf->addrs) {
+ i = 0;
+ while (i < sgbuf->count) {
+ if (!sgbuf->pages[i] || !sgbuf->addrs[i])
+ break;
+ size = sgbuf->addrs[i] & ~PAGE_MASK;
+ if (WARN_ON(!size))
+ break;
+ dma_free_coherent(dmab->dev.dev, size,
+ page_address(sgbuf->pages[i]),
+ sgbuf->addrs[i] & PAGE_MASK);
+ i += size;
+ }
+ }
kvfree(sgbuf->pages);
+ kvfree(sgbuf->addrs);
kfree(sgbuf);
}
@@ -738,9 +752,9 @@ static void *snd_dma_sg_fallback_alloc(struct snd_dma_buffer *dmab, size_t size)
struct snd_dma_sg_fallback *sgbuf;
struct page **pagep, *curp;
size_t chunk, npages;
+ dma_addr_t *addrp;
dma_addr_t addr;
void *p;
- bool wc = dmab->dev.type == SNDRV_DMA_TYPE_DEV_WC_SG_FALLBACK;
sgbuf = kzalloc(sizeof(*sgbuf), GFP_KERNEL);
if (!sgbuf)
@@ -748,14 +762,16 @@ static void *snd_dma_sg_fallback_alloc(struct snd_dma_buffer *dmab, size_t size)
size = PAGE_ALIGN(size);
sgbuf->count = size >> PAGE_SHIFT;
sgbuf->pages = kvcalloc(sgbuf->count, sizeof(*sgbuf->pages), GFP_KERNEL);
- if (!sgbuf->pages)
+ sgbuf->addrs = kvcalloc(sgbuf->count, sizeof(*sgbuf->addrs), GFP_KERNEL);
+ if (!sgbuf->pages || !sgbuf->addrs)
goto error;
pagep = sgbuf->pages;
- chunk = size;
+ addrp = sgbuf->addrs;
+ chunk = (PAGE_SIZE - 1) << PAGE_SHIFT; /* to fit in low bits in addrs */
while (size > 0) {
chunk = min(size, chunk);
- p = do_alloc_pages(dmab->dev.dev, chunk, &addr, wc);
+ p = dma_alloc_coherent(dmab->dev.dev, chunk, &addr, DEFAULT_GFP);
if (!p) {
if (chunk <= PAGE_SIZE)
goto error;
@@ -767,17 +783,25 @@ static void *snd_dma_sg_fallback_alloc(struct snd_dma_buffer *dmab, size_t size)
size -= chunk;
/* fill pages */
npages = chunk >> PAGE_SHIFT;
+ *addrp = npages; /* store in lower bits */
curp = virt_to_page(p);
- while (npages--)
+ while (npages--) {
*pagep++ = curp++;
+ *addrp++ |= addr;
+ addr += PAGE_SIZE;
+ }
}
p = vmap(sgbuf->pages, sgbuf->count, VM_MAP, PAGE_KERNEL);
if (!p)
goto error;
+
+ if (dmab->dev.type == SNDRV_DMA_TYPE_DEV_WC_SG_FALLBACK)
+ set_pages_array_wc(sgbuf->pages, sgbuf->count);
+
dmab->private_data = sgbuf;
/* store the first page address for convenience */
- dmab->addr = snd_sgbuf_get_addr(dmab, 0);
+ dmab->addr = sgbuf->addrs[0] & PAGE_MASK;
return p;
error:
@@ -787,10 +811,23 @@ static void *snd_dma_sg_fallback_alloc(struct snd_dma_buffer *dmab, size_t size)
static void snd_dma_sg_fallback_free(struct snd_dma_buffer *dmab)
{
+ struct snd_dma_sg_fallback *sgbuf = dmab->private_data;
+
vunmap(dmab->area);
+ if (dmab->dev.type == SNDRV_DMA_TYPE_DEV_WC_SG_FALLBACK)
+ set_pages_array_wb(sgbuf->pages, sgbuf->count);
__snd_dma_sg_fallback_free(dmab, dmab->private_data);
}
+static dma_addr_t snd_dma_sg_fallback_get_addr(struct snd_dma_buffer *dmab,
+ size_t offset)
+{
+ struct snd_dma_sg_fallback *sgbuf = dmab->private_data;
+ size_t index = offset >> PAGE_SHIFT;
+
+ return (sgbuf->addrs[index] & PAGE_MASK) | (offset & ~PAGE_MASK);
+}
+
static int snd_dma_sg_fallback_mmap(struct snd_dma_buffer *dmab,
struct vm_area_struct *area)
{
@@ -805,8 +842,8 @@ static const struct snd_malloc_ops snd_dma_sg_fallback_ops = {
.alloc = snd_dma_sg_fallback_alloc,
.free = snd_dma_sg_fallback_free,
.mmap = snd_dma_sg_fallback_mmap,
+ .get_addr = snd_dma_sg_fallback_get_addr,
/* reuse vmalloc helpers */
- .get_addr = snd_dma_vmalloc_get_addr,
.get_page = snd_dma_vmalloc_get_page,
.get_chunk_size = snd_dma_vmalloc_get_chunk_size,
};
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