diff mbox series

[4/3] pcie: minor cleanups for slot control/status

Message ID 20190701093232.28575-1-mst@redhat.com
State New
Headers show
Series pcie: hotplug fixes | expand

Commit Message

Michael S. Tsirkin July 1, 2019, 9:34 a.m. UTC 
Rename function arguments to make intent clearer.
Better documentation for slot control logic.

Suggested-by: Igor Mammedov <imammedo@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---


 include/hw/pci/pcie.h |  3 ++-
 hw/pci/pcie.c         | 17 +++++++++++------
 2 files changed, 13 insertions(+), 7 deletions(-)

Comments

Philippe Mathieu-Daudé July 1, 2019, 9:56 a.m. UTC | #1 
On 7/1/19 11:34 AM, Michael S. Tsirkin wrote:
> Rename function arguments to make intent clearer.
> Better documentation for slot control logic.
> 
> Suggested-by: Igor Mammedov <imammedo@redhat.com>
> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
> ---
> 
> 
>  include/hw/pci/pcie.h |  3 ++-
>  hw/pci/pcie.c         | 17 +++++++++++------
>  2 files changed, 13 insertions(+), 7 deletions(-)
> 
> diff --git a/include/hw/pci/pcie.h b/include/hw/pci/pcie.h
> index 8d90c0e193..34f277735c 100644
> --- a/include/hw/pci/pcie.h
> +++ b/include/hw/pci/pcie.h
> @@ -108,7 +108,8 @@ void pcie_cap_lnkctl_reset(PCIDevice *dev);
>  void pcie_cap_slot_init(PCIDevice *dev, uint16_t slot);
>  void pcie_cap_slot_reset(PCIDevice *dev);
>  void pcie_cap_slot_get(PCIDevice *dev, uint16_t *slot_ctl, uint16_t *slt_sta);
> -void pcie_cap_slot_write_config(PCIDevice *dev, uint16_t slot_ctl, uint16_t slt_sta,
> +void pcie_cap_slot_write_config(PCIDevice *dev,
> +                                uint16_t old_slot_ctl, uint16_t old_slt_sta,
>                                  uint32_t addr, uint32_t val, int len);
>  int pcie_cap_slot_post_load(void *opaque, int version_id);
>  void pcie_cap_slot_push_attention_button(PCIDevice *dev);
> diff --git a/hw/pci/pcie.c b/hw/pci/pcie.c
> index c605d32dd4..a6beb567bd 100644
> --- a/hw/pci/pcie.c
> +++ b/hw/pci/pcie.c
> @@ -602,7 +602,8 @@ void pcie_cap_slot_get(PCIDevice *dev, uint16_t *slt_ctl, uint16_t *slt_sta)
>      *slt_sta = pci_get_word(exp_cap + PCI_EXP_SLTSTA);
>  }
>  
> -void pcie_cap_slot_write_config(PCIDevice *dev, uint16_t slt_ctl, uint16_t slt_sta,
> +void pcie_cap_slot_write_config(PCIDevice *dev,
> +                                uint16_t old_slt_ctl, uint16_t old_slt_sta,
>                                  uint32_t addr, uint32_t val, int len)
>  {
>      uint32_t pos = dev->exp.exp_cap;
> @@ -625,8 +626,8 @@ void pcie_cap_slot_write_config(PCIDevice *dev, uint16_t slt_ctl, uint16_t slt_s
>                            PCI_EXP_SLTSTA_MRLSC | PCI_EXP_SLTSTA_PDC | \
>                            PCI_EXP_SLTSTA_CC)
>  
> -        if (val & ~slt_sta & PCIE_SLOT_EVENTS) {
> -            sltsta = (sltsta & ~PCIE_SLOT_EVENTS) | (slt_sta & PCIE_SLOT_EVENTS);
> +        if (val & ~old_slt_sta & PCIE_SLOT_EVENTS) {
> +            sltsta = (sltsta & ~PCIE_SLOT_EVENTS) | (old_slt_sta & PCIE_SLOT_EVENTS);
>              pci_set_word(exp_cap + PCI_EXP_SLTSTA, sltsta);
>          }
>          hotplug_event_clear(dev);
> @@ -646,13 +647,17 @@ void pcie_cap_slot_write_config(PCIDevice *dev, uint16_t slt_ctl, uint16_t slt_s
>      }
>  
>      /*
> -     * If the slot is polulated, power indicator is off and power
> +     * If the slot is populated, power indicator is off and power
>       * controller is off, it is safe to detach the devices.
> +     *
> +     * Note: don't detach if condition was already true:
> +     * this is a work around for guests that overwrite
> +     * control of powered off slots before powering them on.
>       */
>      if ((sltsta & PCI_EXP_SLTSTA_PDS) && (val & PCI_EXP_SLTCTL_PCC) &&
>          (val & PCI_EXP_SLTCTL_PIC_OFF) == PCI_EXP_SLTCTL_PIC_OFF &&
> -        (!(slt_ctl & PCI_EXP_SLTCTL_PCC) ||
> -        (slt_ctl & PCI_EXP_SLTCTL_PIC_OFF) != PCI_EXP_SLTCTL_PIC_OFF)) {
> +        (!(old_slt_ctl & PCI_EXP_SLTCTL_PCC) ||
> +        (old_slt_ctl & PCI_EXP_SLTCTL_PIC_OFF) != PCI_EXP_SLTCTL_PIC_OFF)) {
>          PCIBus *sec_bus = pci_bridge_get_sec_bus(PCI_BRIDGE(dev));
>          pci_for_each_device(sec_bus, pci_bus_num(sec_bus),
>                              pcie_unplug_device, NULL);
> 

Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Igor Mammedov July 1, 2019, 1:07 p.m. UTC | #2 
On Mon, 1 Jul 2019 05:34:54 -0400
"Michael S. Tsirkin" <mst@redhat.com> wrote:

> Rename function arguments to make intent clearer.
> Better documentation for slot control logic.
> 
> Suggested-by: Igor Mammedov <imammedo@redhat.com>
> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

Reviewed-by: Igor Mammedov <imammedo@redhat.com>


> ---
> 
> 
>  include/hw/pci/pcie.h |  3 ++-
>  hw/pci/pcie.c         | 17 +++++++++++------
>  2 files changed, 13 insertions(+), 7 deletions(-)
> 
> diff --git a/include/hw/pci/pcie.h b/include/hw/pci/pcie.h
> index 8d90c0e193..34f277735c 100644
> --- a/include/hw/pci/pcie.h
> +++ b/include/hw/pci/pcie.h
> @@ -108,7 +108,8 @@ void pcie_cap_lnkctl_reset(PCIDevice *dev);
>  void pcie_cap_slot_init(PCIDevice *dev, uint16_t slot);
>  void pcie_cap_slot_reset(PCIDevice *dev);
>  void pcie_cap_slot_get(PCIDevice *dev, uint16_t *slot_ctl, uint16_t *slt_sta);
> -void pcie_cap_slot_write_config(PCIDevice *dev, uint16_t slot_ctl, uint16_t slt_sta,
> +void pcie_cap_slot_write_config(PCIDevice *dev,
> +                                uint16_t old_slot_ctl, uint16_t old_slt_sta,
>                                  uint32_t addr, uint32_t val, int len);
>  int pcie_cap_slot_post_load(void *opaque, int version_id);
>  void pcie_cap_slot_push_attention_button(PCIDevice *dev);
> diff --git a/hw/pci/pcie.c b/hw/pci/pcie.c
> index c605d32dd4..a6beb567bd 100644
> --- a/hw/pci/pcie.c
> +++ b/hw/pci/pcie.c
> @@ -602,7 +602,8 @@ void pcie_cap_slot_get(PCIDevice *dev, uint16_t *slt_ctl, uint16_t *slt_sta)
>      *slt_sta = pci_get_word(exp_cap + PCI_EXP_SLTSTA);
>  }
>  
> -void pcie_cap_slot_write_config(PCIDevice *dev, uint16_t slt_ctl, uint16_t slt_sta,
> +void pcie_cap_slot_write_config(PCIDevice *dev,
> +                                uint16_t old_slt_ctl, uint16_t old_slt_sta,
>                                  uint32_t addr, uint32_t val, int len)
>  {
>      uint32_t pos = dev->exp.exp_cap;
> @@ -625,8 +626,8 @@ void pcie_cap_slot_write_config(PCIDevice *dev, uint16_t slt_ctl, uint16_t slt_s
>                            PCI_EXP_SLTSTA_MRLSC | PCI_EXP_SLTSTA_PDC | \
>                            PCI_EXP_SLTSTA_CC)
>  
> -        if (val & ~slt_sta & PCIE_SLOT_EVENTS) {
> -            sltsta = (sltsta & ~PCIE_SLOT_EVENTS) | (slt_sta & PCIE_SLOT_EVENTS);
> +        if (val & ~old_slt_sta & PCIE_SLOT_EVENTS) {
> +            sltsta = (sltsta & ~PCIE_SLOT_EVENTS) | (old_slt_sta & PCIE_SLOT_EVENTS);
>              pci_set_word(exp_cap + PCI_EXP_SLTSTA, sltsta);
>          }
>          hotplug_event_clear(dev);
> @@ -646,13 +647,17 @@ void pcie_cap_slot_write_config(PCIDevice *dev, uint16_t slt_ctl, uint16_t slt_s
>      }
>  
>      /*
> -     * If the slot is polulated, power indicator is off and power
> +     * If the slot is populated, power indicator is off and power
>       * controller is off, it is safe to detach the devices.
> +     *
> +     * Note: don't detach if condition was already true:
> +     * this is a work around for guests that overwrite
> +     * control of powered off slots before powering them on.
>       */
>      if ((sltsta & PCI_EXP_SLTSTA_PDS) && (val & PCI_EXP_SLTCTL_PCC) &&
>          (val & PCI_EXP_SLTCTL_PIC_OFF) == PCI_EXP_SLTCTL_PIC_OFF &&
> -        (!(slt_ctl & PCI_EXP_SLTCTL_PCC) ||
> -        (slt_ctl & PCI_EXP_SLTCTL_PIC_OFF) != PCI_EXP_SLTCTL_PIC_OFF)) {
> +        (!(old_slt_ctl & PCI_EXP_SLTCTL_PCC) ||
> +        (old_slt_ctl & PCI_EXP_SLTCTL_PIC_OFF) != PCI_EXP_SLTCTL_PIC_OFF)) {
>          PCIBus *sec_bus = pci_bridge_get_sec_bus(PCI_BRIDGE(dev));
>          pci_for_each_device(sec_bus, pci_bus_num(sec_bus),
>                              pcie_unplug_device, NULL);
Christophe de Dinechin July 1, 2019, 1:51 p.m. UTC | #3 
Michael S. Tsirkin writes:

> Rename function arguments to make intent clearer.
> Better documentation for slot control logic.
>
> Suggested-by: Igor Mammedov <imammedo@redhat.com>
> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
> ---
>
>
>  include/hw/pci/pcie.h |  3 ++-
>  hw/pci/pcie.c         | 17 +++++++++++------
>  2 files changed, 13 insertions(+), 7 deletions(-)
>
> diff --git a/include/hw/pci/pcie.h b/include/hw/pci/pcie.h
> index 8d90c0e193..34f277735c 100644
> --- a/include/hw/pci/pcie.h
> +++ b/include/hw/pci/pcie.h
> @@ -108,7 +108,8 @@ void pcie_cap_lnkctl_reset(PCIDevice *dev);
>  void pcie_cap_slot_init(PCIDevice *dev, uint16_t slot);
>  void pcie_cap_slot_reset(PCIDevice *dev);
>  void pcie_cap_slot_get(PCIDevice *dev, uint16_t *slot_ctl, uint16_t *slt_sta);
> -void pcie_cap_slot_write_config(PCIDevice *dev, uint16_t slot_ctl, uint16_t slt_sta,
> +void pcie_cap_slot_write_config(PCIDevice *dev,
> +                                uint16_t old_slot_ctl, uint16_t old_slt_sta,
>                                  uint32_t addr, uint32_t val, int len);
>  int pcie_cap_slot_post_load(void *opaque, int version_id);
>  void pcie_cap_slot_push_attention_button(PCIDevice *dev);
> diff --git a/hw/pci/pcie.c b/hw/pci/pcie.c
> index c605d32dd4..a6beb567bd 100644
> --- a/hw/pci/pcie.c
> +++ b/hw/pci/pcie.c
> @@ -602,7 +602,8 @@ void pcie_cap_slot_get(PCIDevice *dev, uint16_t *slt_ctl, uint16_t *slt_sta)
>      *slt_sta = pci_get_word(exp_cap + PCI_EXP_SLTSTA);
>  }
>
> -void pcie_cap_slot_write_config(PCIDevice *dev, uint16_t slt_ctl, uint16_t slt_sta,
> +void pcie_cap_slot_write_config(PCIDevice *dev,
> +                                uint16_t old_slt_ctl, uint16_t old_slt_sta,
>                                  uint32_t addr, uint32_t val, int len)
>  {
>      uint32_t pos = dev->exp.exp_cap;
> @@ -625,8 +626,8 @@ void pcie_cap_slot_write_config(PCIDevice *dev, uint16_t slt_ctl, uint16_t slt_s
>                            PCI_EXP_SLTSTA_MRLSC | PCI_EXP_SLTSTA_PDC | \
>                            PCI_EXP_SLTSTA_CC)
>
> -        if (val & ~slt_sta & PCIE_SLOT_EVENTS) {
> -            sltsta = (sltsta & ~PCIE_SLOT_EVENTS) | (slt_sta & PCIE_SLOT_EVENTS);
> +        if (val & ~old_slt_sta & PCIE_SLOT_EVENTS) {
> +            sltsta = (sltsta & ~PCIE_SLOT_EVENTS) | (old_slt_sta & PCIE_SLOT_EVENTS);
>              pci_set_word(exp_cap + PCI_EXP_SLTSTA, sltsta);
>          }
>          hotplug_event_clear(dev);
> @@ -646,13 +647,17 @@ void pcie_cap_slot_write_config(PCIDevice *dev, uint16_t slt_ctl, uint16_t slt_s
>      }
>
>      /*
> -     * If the slot is polulated, power indicator is off and power
> +     * If the slot is populated, power indicator is off and power
>       * controller is off, it is safe to detach the devices.
> +     *
> +     * Note: don't detach if condition was already true:
> +     * this is a work around for guests that overwrite
> +     * control of powered off slots before powering them on.
>       */
>      if ((sltsta & PCI_EXP_SLTSTA_PDS) && (val & PCI_EXP_SLTCTL_PCC) &&
>          (val & PCI_EXP_SLTCTL_PIC_OFF) == PCI_EXP_SLTCTL_PIC_OFF &&
> -        (!(slt_ctl & PCI_EXP_SLTCTL_PCC) ||
> -        (slt_ctl & PCI_EXP_SLTCTL_PIC_OFF) != PCI_EXP_SLTCTL_PIC_OFF)) {
> +        (!(old_slt_ctl & PCI_EXP_SLTCTL_PCC) ||
> +        (old_slt_ctl & PCI_EXP_SLTCTL_PIC_OFF) != PCI_EXP_SLTCTL_PIC_OFF)) {
>          PCIBus *sec_bus = pci_bridge_get_sec_bus(PCI_BRIDGE(dev));
>          pci_for_each_device(sec_bus, pci_bus_num(sec_bus),
>                              pcie_unplug_device, NULL);

Good idea.
Reviewed-by: Christophe de Dinechin <dinechin@redhat.com>

--
Cheers,
Christophe de Dinechin (IRC c3d)
diff mbox series

Patch

diff --git a/include/hw/pci/pcie.h b/include/hw/pci/pcie.h
index 8d90c0e193..34f277735c 100644
--- a/include/hw/pci/pcie.h
+++ b/include/hw/pci/pcie.h
@@ -108,7 +108,8 @@  void pcie_cap_lnkctl_reset(PCIDevice *dev);
 void pcie_cap_slot_init(PCIDevice *dev, uint16_t slot);
 void pcie_cap_slot_reset(PCIDevice *dev);
 void pcie_cap_slot_get(PCIDevice *dev, uint16_t *slot_ctl, uint16_t *slt_sta);
-void pcie_cap_slot_write_config(PCIDevice *dev, uint16_t slot_ctl, uint16_t slt_sta,
+void pcie_cap_slot_write_config(PCIDevice *dev,
+                                uint16_t old_slot_ctl, uint16_t old_slt_sta,
                                 uint32_t addr, uint32_t val, int len);
 int pcie_cap_slot_post_load(void *opaque, int version_id);
 void pcie_cap_slot_push_attention_button(PCIDevice *dev);
diff --git a/hw/pci/pcie.c b/hw/pci/pcie.c
index c605d32dd4..a6beb567bd 100644
--- a/hw/pci/pcie.c
+++ b/hw/pci/pcie.c
@@ -602,7 +602,8 @@  void pcie_cap_slot_get(PCIDevice *dev, uint16_t *slt_ctl, uint16_t *slt_sta)
     *slt_sta = pci_get_word(exp_cap + PCI_EXP_SLTSTA);
 }
 
-void pcie_cap_slot_write_config(PCIDevice *dev, uint16_t slt_ctl, uint16_t slt_sta,
+void pcie_cap_slot_write_config(PCIDevice *dev,
+                                uint16_t old_slt_ctl, uint16_t old_slt_sta,
                                 uint32_t addr, uint32_t val, int len)
 {
     uint32_t pos = dev->exp.exp_cap;
@@ -625,8 +626,8 @@  void pcie_cap_slot_write_config(PCIDevice *dev, uint16_t slt_ctl, uint16_t slt_s
                           PCI_EXP_SLTSTA_MRLSC | PCI_EXP_SLTSTA_PDC | \
                           PCI_EXP_SLTSTA_CC)
 
-        if (val & ~slt_sta & PCIE_SLOT_EVENTS) {
-            sltsta = (sltsta & ~PCIE_SLOT_EVENTS) | (slt_sta & PCIE_SLOT_EVENTS);
+        if (val & ~old_slt_sta & PCIE_SLOT_EVENTS) {
+            sltsta = (sltsta & ~PCIE_SLOT_EVENTS) | (old_slt_sta & PCIE_SLOT_EVENTS);
             pci_set_word(exp_cap + PCI_EXP_SLTSTA, sltsta);
         }
         hotplug_event_clear(dev);
@@ -646,13 +647,17 @@  void pcie_cap_slot_write_config(PCIDevice *dev, uint16_t slt_ctl, uint16_t slt_s
     }
 
     /*
-     * If the slot is polulated, power indicator is off and power
+     * If the slot is populated, power indicator is off and power
      * controller is off, it is safe to detach the devices.
+     *
+     * Note: don't detach if condition was already true:
+     * this is a work around for guests that overwrite
+     * control of powered off slots before powering them on.
      */
     if ((sltsta & PCI_EXP_SLTSTA_PDS) && (val & PCI_EXP_SLTCTL_PCC) &&
         (val & PCI_EXP_SLTCTL_PIC_OFF) == PCI_EXP_SLTCTL_PIC_OFF &&
-        (!(slt_ctl & PCI_EXP_SLTCTL_PCC) ||
-        (slt_ctl & PCI_EXP_SLTCTL_PIC_OFF) != PCI_EXP_SLTCTL_PIC_OFF)) {
+        (!(old_slt_ctl & PCI_EXP_SLTCTL_PCC) ||
+        (old_slt_ctl & PCI_EXP_SLTCTL_PIC_OFF) != PCI_EXP_SLTCTL_PIC_OFF)) {
         PCIBus *sec_bus = pci_bridge_get_sec_bus(PCI_BRIDGE(dev));
         pci_for_each_device(sec_bus, pci_bus_num(sec_bus),
                             pcie_unplug_device, NULL);