Re: [RFC PATCH v4 5/6] xen/vpci: support ro mask

2023-08-31 Thread Jan Beulich
On 28.08.2023 19:56, Stewart Hildebrand wrote:
> Add support for a read-only bit mask for vPCI register handlers.
> 
> Signed-off-by: Stewart Hildebrand 
> ---
> v3->v4:
> * new patch
> 
> RFC: It seemed like a low-hanging fruit to add support for ro mask. Let me 
> know
>  what you think, and I could squash it into the status handler patch for 
> the
>  next version of the series.

I'd be fine having both in one go, fwiw.

Jan



[RFC PATCH v4 5/6] xen/vpci: support ro mask

2023-08-28 Thread Stewart Hildebrand
Add support for a read-only bit mask for vPCI register handlers.

Signed-off-by: Stewart Hildebrand 
---
v3->v4:
* new patch

RFC: It seemed like a low-hanging fruit to add support for ro mask. Let me know
 what you think, and I could squash it into the status handler patch for the
 next version of the series.
---
 xen/drivers/vpci/header.c |  4 ++--
 xen/drivers/vpci/vpci.c   | 15 ++-
 xen/include/xen/vpci.h|  5 +++--
 3 files changed, 15 insertions(+), 9 deletions(-)

diff --git a/xen/drivers/vpci/header.c b/xen/drivers/vpci/header.c
index dc8c6a66770b..4a4dbb69ab1c 100644
--- a/xen/drivers/vpci/header.c
+++ b/xen/drivers/vpci/header.c
@@ -556,8 +556,8 @@ static int cf_check init_bars(struct pci_dev *pdev)
 if ( rc )
 return rc;
 
-rc = vpci_add_rw1c_register(pdev->vpci, status_read, vpci_hw_write16,
-PCI_STATUS, 2, header, 0xF900);
+rc = vpci_add_register_mask(pdev->vpci, status_read, vpci_hw_write16,
+PCI_STATUS, 2, header, 0x06F8, 0xF900);
 if ( rc )
 return rc;
 
diff --git a/xen/drivers/vpci/vpci.c b/xen/drivers/vpci/vpci.c
index 8b26870a8a2b..2a67cc516626 100644
--- a/xen/drivers/vpci/vpci.c
+++ b/xen/drivers/vpci/vpci.c
@@ -29,6 +29,7 @@ struct vpci_register {
 unsigned int offset;
 void *private;
 struct list_head node;
+uint32_t ro_mask;
 uint32_t rw1c_mask;
 };
 
@@ -154,7 +155,8 @@ void cf_check vpci_hw_write16(
 
 static int add_register(struct vpci *vpci, vpci_read_t *read_handler,
 vpci_write_t *write_handler, unsigned int offset,
-unsigned int size, void *data, uint32_t rw1c_mask)
+unsigned int size, void *data, uint32_t ro_mask,
+uint32_t rw1c_mask)
 {
 struct list_head *prev;
 struct vpci_register *r;
@@ -174,6 +176,7 @@ static int add_register(struct vpci *vpci, vpci_read_t 
*read_handler,
 r->size = size;
 r->offset = offset;
 r->private = data;
+r->ro_mask = ro_mask;
 r->rw1c_mask = rw1c_mask;
 
 spin_lock(&vpci->lock);
@@ -206,15 +209,16 @@ int vpci_add_register(struct vpci *vpci, vpci_read_t 
*read_handler,
   unsigned int size, void *data)
 {
 return add_register(vpci, read_handler, write_handler, offset, size, data,
-0);
+0, 0);
 }
 
-int vpci_add_rw1c_register(struct vpci *vpci, vpci_read_t *read_handler,
+int vpci_add_register_mask(struct vpci *vpci, vpci_read_t *read_handler,
vpci_write_t *write_handler, unsigned int offset,
-   unsigned int size, void *data, uint32_t rw1c_mask)
+   unsigned int size, void *data, uint32_t ro_mask,
+   uint32_t rw1c_mask)
 {
 return add_register(vpci, read_handler, write_handler, offset, size, data,
-rw1c_mask);
+ro_mask, rw1c_mask);
 }
 
 int vpci_remove_register(struct vpci *vpci, unsigned int offset,
@@ -447,6 +451,7 @@ static void vpci_write_helper(const struct pci_dev *pdev,
 data = merge_result(val, data, size, offset);
 }
 
+data &= ~r->ro_mask;
 r->write(pdev, r->offset, data & (0xU >> (32 - 8 * r->size)),
  r->private);
 }
diff --git a/xen/include/xen/vpci.h b/xen/include/xen/vpci.h
index 51b1b06c2c71..b0636182d91e 100644
--- a/xen/include/xen/vpci.h
+++ b/xen/include/xen/vpci.h
@@ -37,11 +37,12 @@ int __must_check vpci_add_register(struct vpci *vpci,
vpci_write_t *write_handler,
unsigned int offset, unsigned int size,
void *data);
-int __must_check vpci_add_rw1c_register(struct vpci *vpci,
+int __must_check vpci_add_register_mask(struct vpci *vpci,
 vpci_read_t *read_handler,
 vpci_write_t *write_handler,
 unsigned int offset, unsigned int size,
-void *data, uint32_t rw1c_mask);
+void *data, uint32_t ro_mask,
+uint32_t rw1c_mask);
 int __must_check vpci_remove_register(struct vpci *vpci, unsigned int offset,
   unsigned int size);
 
-- 
2.42.0