| Message ID | 20201121014547.54890-1-decui@microsoft.com (mailing list archive) |
|---|---|
| State | Superseded, archived |
| Headers | show |
| Series | video: hyperv_fb: Directly use the MMIO VRAM | expand |
Hi Dexuan, On Fri, Nov 20, 2020 at 05:45:47PM -0800, Dexuan Cui wrote: > Late in 2019, 2 commits (see the 2 Fixes tags) were introduced to > mitigate the slow framebuffer issue. Now that we have fixed the > slowness issue by correctly mapping the MMIO VRAM (see > commit 5f1251a48c17 ("video: hyperv_fb: Fix the cache type when mapping > the VRAM")), we can remove most of the code introduced by the 2 commits, > i.e. we no longer need to allocate physical memory and use it to back up > the VRAM in Generation-1 VM, and we also no longer need to allocate > physical memory to back up the framebuffer in a Generation-2 VM and copy > the framebuffer to the real VRAM. > > synthvid_deferred_io() is kept, because it's still desirable to send the > SYNTHVID_DIRT message only for the exact dirty rectangle, and only when > needed. > > Fixes: d21987d709e8 ("video: hyperv: hyperv_fb: Support deferred IO for Hyper-V frame buffer driver") > Fixes: 3a6fb6c4255c ("video: hyperv: hyperv_fb: Use physical memory for fb on HyperV Gen 1 VMs.") > Cc: Wei Hu <weh@microsoft.com> > Cc: Boqun Feng <boqun.feng@gmail.com> > Signed-off-by: Dexuan Cui <decui@microsoft.com> After I applied this patch and patch ("video: hyperv_fb: Fix the cache type when mapping the VRAM") on my development branch (with Michael's patchset for ARM64 core support on Hyper-V), and everything worked fine. So feel free to add: Tested-by: Boqun Feng <boqun.feng@gmail.com> Regards, Bqoun > --- > > This patch changes drivers/video/fbdev/Kconfig, but I hope this can > still go through the Hyper-V tree > https://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux.git/log/?h=hyperv-next > because it's unlikely to cause any build issue to other fbdev drivers > (that line was introduced by 3a6fb6c4255c only for hyperv_fb.c) > > Note: this patch is based on the Hyper-V tree's hyperv-fixes branch, but > it should also apply cleanly to the branch hyperv-next if the commit > 5f1251a48c17 is applied first. This patch is for v5.11 rather than > v5.10. > > drivers/video/fbdev/Kconfig | 1 - > drivers/video/fbdev/hyperv_fb.c | 170 ++------------------------------ > 2 files changed, 9 insertions(+), 162 deletions(-) > > diff --git a/drivers/video/fbdev/Kconfig b/drivers/video/fbdev/Kconfig > index 402e85450bb5..05b37fb3c6d6 100644 > --- a/drivers/video/fbdev/Kconfig > +++ b/drivers/video/fbdev/Kconfig > @@ -2205,7 +2205,6 @@ config FB_HYPERV > select FB_CFB_COPYAREA > select FB_CFB_IMAGEBLIT > select FB_DEFERRED_IO > - select DMA_CMA if HAVE_DMA_CONTIGUOUS && CMA > help > This framebuffer driver supports Microsoft Hyper-V Synthetic Video. > > diff --git a/drivers/video/fbdev/hyperv_fb.c b/drivers/video/fbdev/hyperv_fb.c > index 58c74d2356ba..8131f4e66f98 100644 > --- a/drivers/video/fbdev/hyperv_fb.c > +++ b/drivers/video/fbdev/hyperv_fb.c > @@ -31,16 +31,6 @@ > * "set-vmvideo" command. For example > * set-vmvideo -vmname name -horizontalresolution:1920 \ > * -verticalresolution:1200 -resolutiontype single > - * > - * Gen 1 VMs also support direct using VM's physical memory for framebuffer. > - * It could improve the efficiency and performance for framebuffer and VM. > - * This requires to allocate contiguous physical memory from Linux kernel's > - * CMA memory allocator. To enable this, supply a kernel parameter to give > - * enough memory space to CMA allocator for framebuffer. For example: > - * cma=130m > - * This gives 130MB memory to CMA allocator that can be allocated to > - * framebuffer. For reference, 8K resolution (7680x4320) takes about > - * 127MB memory. > */ > > #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt > @@ -267,16 +257,8 @@ struct hvfb_par { > /* If true, the VSC notifies the VSP on every framebuffer change */ > bool synchronous_fb; > > - /* If true, need to copy from deferred IO mem to framebuffer mem */ > - bool need_docopy; > - > struct notifier_block hvfb_panic_nb; > > - /* Memory for deferred IO and frame buffer itself */ > - unsigned char *dio_vp; > - unsigned char *mmio_vp; > - phys_addr_t mmio_pp; > - > /* Dirty rectangle, protected by delayed_refresh_lock */ > int x1, y1, x2, y2; > bool delayed_refresh; > @@ -405,21 +387,6 @@ synthvid_update(struct fb_info *info, int x1, int y1, int x2, int y2) > return 0; > } > > -static void hvfb_docopy(struct hvfb_par *par, > - unsigned long offset, > - unsigned long size) > -{ > - if (!par || !par->mmio_vp || !par->dio_vp || !par->fb_ready || > - size == 0 || offset >= dio_fb_size) > - return; > - > - if (offset + size > dio_fb_size) > - size = dio_fb_size - offset; > - > - memcpy(par->mmio_vp + offset, par->dio_vp + offset, size); > -} > - > -/* Deferred IO callback */ > static void synthvid_deferred_io(struct fb_info *p, > struct list_head *pagelist) > { > @@ -444,10 +411,6 @@ static void synthvid_deferred_io(struct fb_info *p, > y2 = end / p->fix.line_length; > miny = min_t(int, miny, y1); > maxy = max_t(int, maxy, y2); > - > - /* Copy from dio space to mmio address */ > - if (par->fb_ready && par->need_docopy) > - hvfb_docopy(par, start, PAGE_SIZE); > } > > if (par->fb_ready && par->update) > @@ -704,7 +667,7 @@ static int synthvid_send_config(struct hv_device *hdev) > msg->vid_hdr.type = SYNTHVID_VRAM_LOCATION; > msg->vid_hdr.size = sizeof(struct synthvid_msg_hdr) + > sizeof(struct synthvid_vram_location); > - msg->vram.user_ctx = msg->vram.vram_gpa = par->mmio_pp; > + msg->vram.user_ctx = msg->vram.vram_gpa = info->fix.smem_start; > msg->vram.is_vram_gpa_specified = 1; > synthvid_send(hdev, msg); > > @@ -714,7 +677,7 @@ static int synthvid_send_config(struct hv_device *hdev) > ret = -ETIMEDOUT; > goto out; > } > - if (msg->vram_ack.user_ctx != par->mmio_pp) { > + if (msg->vram_ack.user_ctx != info->fix.smem_start) { > pr_err("Unable to set VRAM location\n"); > ret = -ENODEV; > goto out; > @@ -740,7 +703,6 @@ static void hvfb_update_work(struct work_struct *w) > struct fb_info *info = par->info; > unsigned long flags; > int x1, x2, y1, y2; > - int j; > > spin_lock_irqsave(&par->delayed_refresh_lock, flags); > /* Reset the request flag */ > @@ -762,14 +724,6 @@ static void hvfb_update_work(struct work_struct *w) > y1 > info->var.yres || y2 > info->var.yres || x2 <= x1) > return; > > - /* Copy the dirty rectangle to frame buffer memory */ > - if (par->need_docopy) > - for (j = y1; j < y2; j++) > - hvfb_docopy(par, > - j * info->fix.line_length + > - (x1 * screen_depth / 8), > - (x2 - x1) * screen_depth / 8); > - > /* Refresh */ > if (par->fb_ready && par->update) > synthvid_update(info, x1, y1, x2, y2); > @@ -813,8 +767,6 @@ static int hvfb_on_panic(struct notifier_block *nb, > par = container_of(nb, struct hvfb_par, hvfb_panic_nb); > par->synchronous_fb = true; > info = par->info; > - if (par->need_docopy) > - hvfb_docopy(par, 0, dio_fb_size); > synthvid_update(info, 0, 0, INT_MAX, INT_MAX); > > return NOTIFY_DONE; > @@ -953,62 +905,6 @@ static void hvfb_get_option(struct fb_info *info) > return; > } > > -/* > - * Allocate enough contiguous physical memory. > - * Return physical address if succeeded or -1 if failed. > - */ > -static phys_addr_t hvfb_get_phymem(struct hv_device *hdev, > - unsigned int request_size) > -{ > - struct page *page = NULL; > - dma_addr_t dma_handle; > - void *vmem; > - phys_addr_t paddr = 0; > - unsigned int order = get_order(request_size); > - > - if (request_size == 0) > - return -1; > - > - if (order < MAX_ORDER) { > - /* Call alloc_pages if the size is less than 2^MAX_ORDER */ > - page = alloc_pages(GFP_KERNEL | __GFP_ZERO, order); > - if (!page) > - return -1; > - > - paddr = (page_to_pfn(page) << PAGE_SHIFT); > - } else { > - /* Allocate from CMA */ > - hdev->device.coherent_dma_mask = DMA_BIT_MASK(64); > - > - vmem = dma_alloc_coherent(&hdev->device, > - round_up(request_size, PAGE_SIZE), > - &dma_handle, > - GFP_KERNEL | __GFP_NOWARN); > - > - if (!vmem) > - return -1; > - > - paddr = virt_to_phys(vmem); > - } > - > - return paddr; > -} > - > -/* Release contiguous physical memory */ > -static void hvfb_release_phymem(struct hv_device *hdev, > - phys_addr_t paddr, unsigned int size) > -{ > - unsigned int order = get_order(size); > - > - if (order < MAX_ORDER) > - __free_pages(pfn_to_page(paddr >> PAGE_SHIFT), order); > - else > - dma_free_coherent(&hdev->device, > - round_up(size, PAGE_SIZE), > - phys_to_virt(paddr), > - paddr); > -} > - > > /* Get framebuffer memory from Hyper-V video pci space */ > static int hvfb_getmem(struct hv_device *hdev, struct fb_info *info) > @@ -1018,7 +914,6 @@ static int hvfb_getmem(struct hv_device *hdev, struct fb_info *info) > void __iomem *fb_virt; > int gen2vm = efi_enabled(EFI_BOOT); > resource_size_t pot_start, pot_end; > - phys_addr_t paddr; > int ret; > > info->apertures = alloc_apertures(1); > @@ -1036,38 +931,12 @@ static int hvfb_getmem(struct hv_device *hdev, struct fb_info *info) > > info->apertures->ranges[0].base = pci_resource_start(pdev, 0); > info->apertures->ranges[0].size = pci_resource_len(pdev, 0); > - > - /* > - * For Gen 1 VM, we can directly use the contiguous memory > - * from VM. If we succeed, deferred IO happens directly > - * on this allocated framebuffer memory, avoiding extra > - * memory copy. > - */ > - paddr = hvfb_get_phymem(hdev, screen_fb_size); > - if (paddr != (phys_addr_t) -1) { > - par->mmio_pp = paddr; > - par->mmio_vp = par->dio_vp = __va(paddr); > - > - info->fix.smem_start = paddr; > - info->fix.smem_len = screen_fb_size; > - info->screen_base = par->mmio_vp; > - info->screen_size = screen_fb_size; > - > - par->need_docopy = false; > - goto getmem_done; > - } > - pr_info("Unable to allocate enough contiguous physical memory on Gen 1 VM. Using MMIO instead.\n"); > } else { > info->apertures->ranges[0].base = screen_info.lfb_base; > info->apertures->ranges[0].size = screen_info.lfb_size; > } > > - /* > - * Cannot use the contiguous physical memory. > - * Allocate mmio space for framebuffer. > - */ > - dio_fb_size = > - screen_width * screen_height * screen_depth / 8; > + dio_fb_size = screen_width * screen_height * screen_depth / 8; > > if (gen2vm) { > pot_start = 0; > @@ -1101,22 +970,11 @@ static int hvfb_getmem(struct hv_device *hdev, struct fb_info *info) > if (!fb_virt) > goto err2; > > - /* Allocate memory for deferred IO */ > - par->dio_vp = vzalloc(round_up(dio_fb_size, PAGE_SIZE)); > - if (par->dio_vp == NULL) > - goto err3; > - > - /* Physical address of FB device */ > - par->mmio_pp = par->mem->start; > - /* Virtual address of FB device */ > - par->mmio_vp = (unsigned char *) fb_virt; > - > info->fix.smem_start = par->mem->start; > info->fix.smem_len = dio_fb_size; > - info->screen_base = par->dio_vp; > + info->screen_base = fb_virt; > info->screen_size = dio_fb_size; > > -getmem_done: > remove_conflicting_framebuffers(info->apertures, > KBUILD_MODNAME, false); > if (!gen2vm) > @@ -1125,8 +983,6 @@ static int hvfb_getmem(struct hv_device *hdev, struct fb_info *info) > > return 0; > > -err3: > - iounmap(fb_virt); > err2: > vmbus_free_mmio(par->mem->start, screen_fb_size); > par->mem = NULL; > @@ -1139,19 +995,12 @@ static int hvfb_getmem(struct hv_device *hdev, struct fb_info *info) > } > > /* Release the framebuffer */ > -static void hvfb_putmem(struct hv_device *hdev, struct fb_info *info) > +static void hvfb_putmem(struct fb_info *info) > { > struct hvfb_par *par = info->par; > > - if (par->need_docopy) { > - vfree(par->dio_vp); > - iounmap(info->screen_base); > - vmbus_free_mmio(par->mem->start, screen_fb_size); > - } else { > - hvfb_release_phymem(hdev, info->fix.smem_start, > - screen_fb_size); > - } > - > + iounmap(info->screen_base); > + vmbus_free_mmio(par->mem->start, screen_fb_size); > par->mem = NULL; > } > > @@ -1170,7 +1019,6 @@ static int hvfb_probe(struct hv_device *hdev, > par = info->par; > par->info = info; > par->fb_ready = false; > - par->need_docopy = true; > init_completion(&par->wait); > INIT_DELAYED_WORK(&par->dwork, hvfb_update_work); > > @@ -1256,7 +1104,7 @@ static int hvfb_probe(struct hv_device *hdev, > > error: > fb_deferred_io_cleanup(info); > - hvfb_putmem(hdev, info); > + hvfb_putmem(info); > error2: > vmbus_close(hdev->channel); > error1: > @@ -1286,7 +1134,7 @@ static int hvfb_remove(struct hv_device *hdev) > vmbus_close(hdev->channel); > hv_set_drvdata(hdev, NULL); > > - hvfb_putmem(hdev, info); > + hvfb_putmem(info); > framebuffer_release(info); > > return 0; > -- > 2.19.1 >
Hi Wei Liu,
Please do not pick up this patch, because actually MMIO VRAM can not work
with fb_deferred_io.
Previously I didn't test Xorg -- sorry. As soon as I tested it, I got the below
warning and the Xorg program ternimated immediately:
[ 28.148432] WARNING: CPU: 19 PID: 1410 at mm/vmalloc.c:383 vmalloc_to_page+0x14b/0x150
...
[ 28.192959] CPU: 19 PID: 1410 Comm: Xorg Tainted: G E 5.10.0-rc1+ #4
...
[ 28.208720] RIP: 0010:vmalloc_to_page+0x14b/0x150
...
[ 28.299231] Call Trace:
[ 28.301428] fb_deferred_io_fault+0x3a/0xa0
[ 28.305276] __do_fault+0x36/0x120
[ 28.308276] handle_mm_fault+0x1144/0x1950
[ 28.311963] exc_page_fault+0x290/0x510
[ 28.315551] ? asm_exc_page_fault+0x8/0x30
[ 28.319186] asm_exc_page_fault+0x1e/0x30
[ 28.322969] RIP: 0033:0x7fbeda3ec2f5
The issue is that fb_deferred_io_page() requires that the PFN be backed by a
struct page, but it looks the MMIO address does not have the struct page backed.
So I have to drop this patch.
Thanks Wei Hu and Michael for pointing this out!
FYI: drivers/video/fbdev/core/fb_defio.c:
static struct page *fb_deferred_io_page(struct fb_info *info, unsigned long offs)
{
void *screen_base = (void __force *) info->screen_base;
struct page *page;
if (is_vmalloc_addr(screen_base + offs))
page = vmalloc_to_page(screen_base + offs);
else
page = pfn_to_page((info->fix.smem_start + offs) >> PAGE_SHIFT);
return page;
}
/* this is to find and return the vmalloc-ed fb pages */
static vm_fault_t fb_deferred_io_fault(struct vm_fault *vmf)
{
unsigned long offset;
struct page *page;
struct fb_info *info = vmf->vma->vm_private_data;
offset = vmf->pgoff << PAGE_SHIFT;
if (offset >= info->fix.smem_len)
return VM_FAULT_SIGBUS;
page = fb_deferred_io_page(info, offset);
if (!page)
return VM_FAULT_SIGBUS;
Thanks,
-- Dexuan
On Tue, Nov 24, 2020 at 08:33:32AM +0000, Dexuan Cui wrote: > Hi Wei Liu, > Please do not pick up this patch, because actually MMIO VRAM can not work > with fb_deferred_io. > No problem. Thanks for the heads-up. Wei.
diff --git a/drivers/video/fbdev/Kconfig b/drivers/video/fbdev/Kconfig index 402e85450bb5..05b37fb3c6d6 100644 --- a/drivers/video/fbdev/Kconfig +++ b/drivers/video/fbdev/Kconfig @@ -2205,7 +2205,6 @@ config FB_HYPERV select FB_CFB_COPYAREA select FB_CFB_IMAGEBLIT select FB_DEFERRED_IO - select DMA_CMA if HAVE_DMA_CONTIGUOUS && CMA help This framebuffer driver supports Microsoft Hyper-V Synthetic Video. diff --git a/drivers/video/fbdev/hyperv_fb.c b/drivers/video/fbdev/hyperv_fb.c index 58c74d2356ba..8131f4e66f98 100644 --- a/drivers/video/fbdev/hyperv_fb.c +++ b/drivers/video/fbdev/hyperv_fb.c @@ -31,16 +31,6 @@ * "set-vmvideo" command. For example * set-vmvideo -vmname name -horizontalresolution:1920 \ * -verticalresolution:1200 -resolutiontype single - * - * Gen 1 VMs also support direct using VM's physical memory for framebuffer. - * It could improve the efficiency and performance for framebuffer and VM. - * This requires to allocate contiguous physical memory from Linux kernel's - * CMA memory allocator. To enable this, supply a kernel parameter to give - * enough memory space to CMA allocator for framebuffer. For example: - * cma=130m - * This gives 130MB memory to CMA allocator that can be allocated to - * framebuffer. For reference, 8K resolution (7680x4320) takes about - * 127MB memory. */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt @@ -267,16 +257,8 @@ struct hvfb_par { /* If true, the VSC notifies the VSP on every framebuffer change */ bool synchronous_fb; - /* If true, need to copy from deferred IO mem to framebuffer mem */ - bool need_docopy; - struct notifier_block hvfb_panic_nb; - /* Memory for deferred IO and frame buffer itself */ - unsigned char *dio_vp; - unsigned char *mmio_vp; - phys_addr_t mmio_pp; - /* Dirty rectangle, protected by delayed_refresh_lock */ int x1, y1, x2, y2; bool delayed_refresh; @@ -405,21 +387,6 @@ synthvid_update(struct fb_info *info, int x1, int y1, int x2, int y2) return 0; } -static void hvfb_docopy(struct hvfb_par *par, - unsigned long offset, - unsigned long size) -{ - if (!par || !par->mmio_vp || !par->dio_vp || !par->fb_ready || - size == 0 || offset >= dio_fb_size) - return; - - if (offset + size > dio_fb_size) - size = dio_fb_size - offset; - - memcpy(par->mmio_vp + offset, par->dio_vp + offset, size); -} - -/* Deferred IO callback */ static void synthvid_deferred_io(struct fb_info *p, struct list_head *pagelist) { @@ -444,10 +411,6 @@ static void synthvid_deferred_io(struct fb_info *p, y2 = end / p->fix.line_length; miny = min_t(int, miny, y1); maxy = max_t(int, maxy, y2); - - /* Copy from dio space to mmio address */ - if (par->fb_ready && par->need_docopy) - hvfb_docopy(par, start, PAGE_SIZE); } if (par->fb_ready && par->update) @@ -704,7 +667,7 @@ static int synthvid_send_config(struct hv_device *hdev) msg->vid_hdr.type = SYNTHVID_VRAM_LOCATION; msg->vid_hdr.size = sizeof(struct synthvid_msg_hdr) + sizeof(struct synthvid_vram_location); - msg->vram.user_ctx = msg->vram.vram_gpa = par->mmio_pp; + msg->vram.user_ctx = msg->vram.vram_gpa = info->fix.smem_start; msg->vram.is_vram_gpa_specified = 1; synthvid_send(hdev, msg); @@ -714,7 +677,7 @@ static int synthvid_send_config(struct hv_device *hdev) ret = -ETIMEDOUT; goto out; } - if (msg->vram_ack.user_ctx != par->mmio_pp) { + if (msg->vram_ack.user_ctx != info->fix.smem_start) { pr_err("Unable to set VRAM location\n"); ret = -ENODEV; goto out; @@ -740,7 +703,6 @@ static void hvfb_update_work(struct work_struct *w) struct fb_info *info = par->info; unsigned long flags; int x1, x2, y1, y2; - int j; spin_lock_irqsave(&par->delayed_refresh_lock, flags); /* Reset the request flag */ @@ -762,14 +724,6 @@ static void hvfb_update_work(struct work_struct *w) y1 > info->var.yres || y2 > info->var.yres || x2 <= x1) return; - /* Copy the dirty rectangle to frame buffer memory */ - if (par->need_docopy) - for (j = y1; j < y2; j++) - hvfb_docopy(par, - j * info->fix.line_length + - (x1 * screen_depth / 8), - (x2 - x1) * screen_depth / 8); - /* Refresh */ if (par->fb_ready && par->update) synthvid_update(info, x1, y1, x2, y2); @@ -813,8 +767,6 @@ static int hvfb_on_panic(struct notifier_block *nb, par = container_of(nb, struct hvfb_par, hvfb_panic_nb); par->synchronous_fb = true; info = par->info; - if (par->need_docopy) - hvfb_docopy(par, 0, dio_fb_size); synthvid_update(info, 0, 0, INT_MAX, INT_MAX); return NOTIFY_DONE; @@ -953,62 +905,6 @@ static void hvfb_get_option(struct fb_info *info) return; } -/* - * Allocate enough contiguous physical memory. - * Return physical address if succeeded or -1 if failed. - */ -static phys_addr_t hvfb_get_phymem(struct hv_device *hdev, - unsigned int request_size) -{ - struct page *page = NULL; - dma_addr_t dma_handle; - void *vmem; - phys_addr_t paddr = 0; - unsigned int order = get_order(request_size); - - if (request_size == 0) - return -1; - - if (order < MAX_ORDER) { - /* Call alloc_pages if the size is less than 2^MAX_ORDER */ - page = alloc_pages(GFP_KERNEL | __GFP_ZERO, order); - if (!page) - return -1; - - paddr = (page_to_pfn(page) << PAGE_SHIFT); - } else { - /* Allocate from CMA */ - hdev->device.coherent_dma_mask = DMA_BIT_MASK(64); - - vmem = dma_alloc_coherent(&hdev->device, - round_up(request_size, PAGE_SIZE), - &dma_handle, - GFP_KERNEL | __GFP_NOWARN); - - if (!vmem) - return -1; - - paddr = virt_to_phys(vmem); - } - - return paddr; -} - -/* Release contiguous physical memory */ -static void hvfb_release_phymem(struct hv_device *hdev, - phys_addr_t paddr, unsigned int size) -{ - unsigned int order = get_order(size); - - if (order < MAX_ORDER) - __free_pages(pfn_to_page(paddr >> PAGE_SHIFT), order); - else - dma_free_coherent(&hdev->device, - round_up(size, PAGE_SIZE), - phys_to_virt(paddr), - paddr); -} - /* Get framebuffer memory from Hyper-V video pci space */ static int hvfb_getmem(struct hv_device *hdev, struct fb_info *info) @@ -1018,7 +914,6 @@ static int hvfb_getmem(struct hv_device *hdev, struct fb_info *info) void __iomem *fb_virt; int gen2vm = efi_enabled(EFI_BOOT); resource_size_t pot_start, pot_end; - phys_addr_t paddr; int ret; info->apertures = alloc_apertures(1); @@ -1036,38 +931,12 @@ static int hvfb_getmem(struct hv_device *hdev, struct fb_info *info) info->apertures->ranges[0].base = pci_resource_start(pdev, 0); info->apertures->ranges[0].size = pci_resource_len(pdev, 0); - - /* - * For Gen 1 VM, we can directly use the contiguous memory - * from VM. If we succeed, deferred IO happens directly - * on this allocated framebuffer memory, avoiding extra - * memory copy. - */ - paddr = hvfb_get_phymem(hdev, screen_fb_size); - if (paddr != (phys_addr_t) -1) { - par->mmio_pp = paddr; - par->mmio_vp = par->dio_vp = __va(paddr); - - info->fix.smem_start = paddr; - info->fix.smem_len = screen_fb_size; - info->screen_base = par->mmio_vp; - info->screen_size = screen_fb_size; - - par->need_docopy = false; - goto getmem_done; - } - pr_info("Unable to allocate enough contiguous physical memory on Gen 1 VM. Using MMIO instead.\n"); } else { info->apertures->ranges[0].base = screen_info.lfb_base; info->apertures->ranges[0].size = screen_info.lfb_size; } - /* - * Cannot use the contiguous physical memory. - * Allocate mmio space for framebuffer. - */ - dio_fb_size = - screen_width * screen_height * screen_depth / 8; + dio_fb_size = screen_width * screen_height * screen_depth / 8; if (gen2vm) { pot_start = 0; @@ -1101,22 +970,11 @@ static int hvfb_getmem(struct hv_device *hdev, struct fb_info *info) if (!fb_virt) goto err2; - /* Allocate memory for deferred IO */ - par->dio_vp = vzalloc(round_up(dio_fb_size, PAGE_SIZE)); - if (par->dio_vp == NULL) - goto err3; - - /* Physical address of FB device */ - par->mmio_pp = par->mem->start; - /* Virtual address of FB device */ - par->mmio_vp = (unsigned char *) fb_virt; - info->fix.smem_start = par->mem->start; info->fix.smem_len = dio_fb_size; - info->screen_base = par->dio_vp; + info->screen_base = fb_virt; info->screen_size = dio_fb_size; -getmem_done: remove_conflicting_framebuffers(info->apertures, KBUILD_MODNAME, false); if (!gen2vm) @@ -1125,8 +983,6 @@ static int hvfb_getmem(struct hv_device *hdev, struct fb_info *info) return 0; -err3: - iounmap(fb_virt); err2: vmbus_free_mmio(par->mem->start, screen_fb_size); par->mem = NULL; @@ -1139,19 +995,12 @@ static int hvfb_getmem(struct hv_device *hdev, struct fb_info *info) } /* Release the framebuffer */ -static void hvfb_putmem(struct hv_device *hdev, struct fb_info *info) +static void hvfb_putmem(struct fb_info *info) { struct hvfb_par *par = info->par; - if (par->need_docopy) { - vfree(par->dio_vp); - iounmap(info->screen_base); - vmbus_free_mmio(par->mem->start, screen_fb_size); - } else { - hvfb_release_phymem(hdev, info->fix.smem_start, - screen_fb_size); - } - + iounmap(info->screen_base); + vmbus_free_mmio(par->mem->start, screen_fb_size); par->mem = NULL; } @@ -1170,7 +1019,6 @@ static int hvfb_probe(struct hv_device *hdev, par = info->par; par->info = info; par->fb_ready = false; - par->need_docopy = true; init_completion(&par->wait); INIT_DELAYED_WORK(&par->dwork, hvfb_update_work); @@ -1256,7 +1104,7 @@ static int hvfb_probe(struct hv_device *hdev, error: fb_deferred_io_cleanup(info); - hvfb_putmem(hdev, info); + hvfb_putmem(info); error2: vmbus_close(hdev->channel); error1: @@ -1286,7 +1134,7 @@ static int hvfb_remove(struct hv_device *hdev) vmbus_close(hdev->channel); hv_set_drvdata(hdev, NULL); - hvfb_putmem(hdev, info); + hvfb_putmem(info); framebuffer_release(info); return 0;
Late in 2019, 2 commits (see the 2 Fixes tags) were introduced to mitigate the slow framebuffer issue. Now that we have fixed the slowness issue by correctly mapping the MMIO VRAM (see commit 5f1251a48c17 ("video: hyperv_fb: Fix the cache type when mapping the VRAM")), we can remove most of the code introduced by the 2 commits, i.e. we no longer need to allocate physical memory and use it to back up the VRAM in Generation-1 VM, and we also no longer need to allocate physical memory to back up the framebuffer in a Generation-2 VM and copy the framebuffer to the real VRAM. synthvid_deferred_io() is kept, because it's still desirable to send the SYNTHVID_DIRT message only for the exact dirty rectangle, and only when needed. Fixes: d21987d709e8 ("video: hyperv: hyperv_fb: Support deferred IO for Hyper-V frame buffer driver") Fixes: 3a6fb6c4255c ("video: hyperv: hyperv_fb: Use physical memory for fb on HyperV Gen 1 VMs.") Cc: Wei Hu <weh@microsoft.com> Cc: Boqun Feng <boqun.feng@gmail.com> Signed-off-by: Dexuan Cui <decui@microsoft.com> --- This patch changes drivers/video/fbdev/Kconfig, but I hope this can still go through the Hyper-V tree https://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux.git/log/?h=hyperv-next because it's unlikely to cause any build issue to other fbdev drivers (that line was introduced by 3a6fb6c4255c only for hyperv_fb.c) Note: this patch is based on the Hyper-V tree's hyperv-fixes branch, but it should also apply cleanly to the branch hyperv-next if the commit 5f1251a48c17 is applied first. This patch is for v5.11 rather than v5.10. drivers/video/fbdev/Kconfig | 1 - drivers/video/fbdev/hyperv_fb.c | 170 ++------------------------------ 2 files changed, 9 insertions(+), 162 deletions(-)