intel_th: msu: Fix vmalloced buffers

After commit f5ff79fd ("dma-mapping: remove CONFIG_DMA_REMAP") there's
a chance of DMA buffer getting allocated via vmalloc(), which messes up
the mmapping code:

> RIP: msc_mmap_fault [intel_th_msu]
> Call Trace:
>  <TASK>
>  __do_fault
>  do_fault
...

Fix this by accounting for vmalloc possibility.

Fixes: ba39bd83 ("intel_th: msu: Switch over to scatterlist")
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Link: https://lore.kernel.org/r/20220705082637.59979-4-alexander.shishkin@linux.intel.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/hwtracing/intel_th/msu.c

@@ -1067,6 +1067,16 @@ msc_buffer_set_uc(struct msc *msc) {}
 static inline void msc_buffer_set_wb(struct msc *msc) {}
 #endif /* CONFIG_X86 */
 
+static struct page *msc_sg_page(struct scatterlist *sg)
+{
+	void *addr = sg_virt(sg);
+
+	if (is_vmalloc_addr(addr))
+		return vmalloc_to_page(addr);
+
+	return sg_page(sg);
+}
+
 /**
  * msc_buffer_win_alloc() - alloc a window for a multiblock mode
  * @msc:	MSC device
@@ -1137,7 +1147,7 @@ static void __msc_buffer_win_free(struct msc *msc, struct msc_window *win)
 	int i;
 
 	for_each_sg(win->sgt->sgl, sg, win->nr_segs, i) {
-		struct page *page = sg_page(sg);
+		struct page *page = msc_sg_page(sg);
 
 		page->mapping = NULL;
 		dma_free_coherent(msc_dev(win->msc)->parent->parent, PAGE_SIZE,
@@ -1401,7 +1411,7 @@ static struct page *msc_buffer_get_page(struct msc *msc, unsigned long pgoff)
 	pgoff -= win->pgoff;
 
 	for_each_sg(win->sgt->sgl, sg, win->nr_segs, blk) {
-		struct page *page = sg_page(sg);
+		struct page *page = msc_sg_page(sg);
 		size_t pgsz = PFN_DOWN(sg->length);
 
 		if (pgoff < pgsz)