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* [PATCH 0/3] Support xen-driven USB3 debug capability
@ 2021-05-12  0:18 Connor Davis
  2021-05-12  0:18 ` [PATCH 1/3] usb: early: Avoid using DbC if already enabled Connor Davis
                   ` (2 more replies)
  0 siblings, 3 replies; 11+ messages in thread
From: Connor Davis @ 2021-05-12  0:18 UTC (permalink / raw)
  To: linux-kernel
  Cc: Connor Davis, linux-usb, xen-devel, Greg Kroah-Hartman,
	Lee Jones, Jann Horn, Chunfeng Yun, Boris Ostrovsky,
	Juergen Gross, Stefano Stabellini, Mathias Nyman

Hi all,

This goal of this series is to allow the USB3 debug capability (DbC) to be
safely used by xen while linux runs as dom0. The first patch prevents
the early DbC driver from using an already-running DbC. The second
exports xen_dbgp_reset_prep and xen_dbgp_external_startup functions when
CONFIG_XEN_DOM0 is enabled so they may be used by the xHCI driver.
The last uses those functions to notify xen of unsafe periods (e.g. reset
and D3hot transition).

Thanks,
Connor

--
Connor Davis (3):
  usb: early: Avoid using DbC if already enabled
  xen: Export dbgp functions when CONFIG_XEN_DOM0 is enabled
  usb: xhci: Notify xen when DbC is unsafe to use

 drivers/usb/early/xhci-dbc.c   | 10 ++++++
 drivers/usb/host/xhci-dbgcap.h |  6 ++++
 drivers/usb/host/xhci.c        | 57 ++++++++++++++++++++++++++++++++++
 drivers/usb/host/xhci.h        |  1 +
 drivers/xen/dbgp.c             |  2 +-
 5 files changed, 75 insertions(+), 1 deletion(-)


base-commit: 88b06399c9c766c283e070b022b5ceafa4f63f19
--
2.31.1



^ permalink raw reply	[flat|nested] 11+ messages in thread

* [PATCH 1/3] usb: early: Avoid using DbC if already enabled
  2021-05-12  0:18 [PATCH 0/3] Support xen-driven USB3 debug capability Connor Davis
@ 2021-05-12  0:18 ` Connor Davis
  2021-05-12  0:18 ` [PATCH 2/3] xen: Export dbgp functions when CONFIG_XEN_DOM0 is enabled Connor Davis
  2021-05-12  0:18 ` [PATCH 3/3] usb: xhci: Notify xen when DbC is unsafe to use Connor Davis
  2 siblings, 0 replies; 11+ messages in thread
From: Connor Davis @ 2021-05-12  0:18 UTC (permalink / raw)
  To: Greg Kroah-Hartman
  Cc: Connor Davis, Lee Jones, Jann Horn, Chunfeng Yun, xen-devel,
	linux-usb, linux-kernel

Check if the debug capability is enabled in early_xdbc_parse_parameter,
and if it is, return with an error. This avoids collisions with whatever
enabled the DbC prior to linux starting.

Signed-off-by: Connor Davis <connojdavis@gmail.com>
---
 drivers/usb/early/xhci-dbc.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/drivers/usb/early/xhci-dbc.c b/drivers/usb/early/xhci-dbc.c
index be4ecbabdd58..ca67fddc2d36 100644
--- a/drivers/usb/early/xhci-dbc.c
+++ b/drivers/usb/early/xhci-dbc.c
@@ -642,6 +642,16 @@ int __init early_xdbc_parse_parameter(char *s)
 	}
 	xdbc.xdbc_reg = (struct xdbc_regs __iomem *)(xdbc.xhci_base + offset);

+	if (readl(&xdbc.xdbc_reg->control) & CTRL_DBC_ENABLE) {
+		pr_notice("xhci debug capability already in use\n");
+		early_iounmap(xdbc.xhci_base, xdbc.xhci_length);
+		xdbc.xdbc_reg = NULL;
+		xdbc.xhci_base = NULL;
+		xdbc.xhci_length = 0;
+
+		return -ENODEV;
+	}
+
 	return 0;
 }

--
2.31.1



^ permalink raw reply	[flat|nested] 11+ messages in thread

* [PATCH 2/3] xen: Export dbgp functions when CONFIG_XEN_DOM0 is enabled
  2021-05-12  0:18 [PATCH 0/3] Support xen-driven USB3 debug capability Connor Davis
  2021-05-12  0:18 ` [PATCH 1/3] usb: early: Avoid using DbC if already enabled Connor Davis
@ 2021-05-12  0:18 ` Connor Davis
  2021-05-12  5:41   ` Juergen Gross
  2021-05-12 13:54   ` Boris Ostrovsky
  2021-05-12  0:18 ` [PATCH 3/3] usb: xhci: Notify xen when DbC is unsafe to use Connor Davis
  2 siblings, 2 replies; 11+ messages in thread
From: Connor Davis @ 2021-05-12  0:18 UTC (permalink / raw)
  To: Boris Ostrovsky, Juergen Gross, Stefano Stabellini
  Cc: Connor Davis, xen-devel, linux-kernel

Export xen_dbgp_reset_prep and xen_dbgp_external_startup
when CONFIG_XEN_DOM0 is defined. This allows use of these symbols
even if CONFIG_EARLY_PRINK_DBGP is defined.

Signed-off-by: Connor Davis <connojdavis@gmail.com>
---
 drivers/xen/dbgp.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/xen/dbgp.c b/drivers/xen/dbgp.c
index cfb5de31d860..fef32dd1a5dc 100644
--- a/drivers/xen/dbgp.c
+++ b/drivers/xen/dbgp.c
@@ -44,7 +44,7 @@ int xen_dbgp_external_startup(struct usb_hcd *hcd)
 	return xen_dbgp_op(hcd, PHYSDEVOP_DBGP_RESET_DONE);
 }

-#ifndef CONFIG_EARLY_PRINTK_DBGP
+#if defined(CONFIG_XEN_DOM0) || !defined(CONFIG_EARLY_PRINTK_DBGP)
 #include <linux/export.h>
 EXPORT_SYMBOL_GPL(xen_dbgp_reset_prep);
 EXPORT_SYMBOL_GPL(xen_dbgp_external_startup);
--
2.31.1



^ permalink raw reply	[flat|nested] 11+ messages in thread

* [PATCH 3/3] usb: xhci: Notify xen when DbC is unsafe to use
  2021-05-12  0:18 [PATCH 0/3] Support xen-driven USB3 debug capability Connor Davis
  2021-05-12  0:18 ` [PATCH 1/3] usb: early: Avoid using DbC if already enabled Connor Davis
  2021-05-12  0:18 ` [PATCH 2/3] xen: Export dbgp functions when CONFIG_XEN_DOM0 is enabled Connor Davis
@ 2021-05-12  0:18 ` Connor Davis
  2021-05-12  7:03   ` Greg Kroah-Hartman
  2 siblings, 1 reply; 11+ messages in thread
From: Connor Davis @ 2021-05-12  0:18 UTC (permalink / raw)
  To: Greg Kroah-Hartman
  Cc: Connor Davis, Mathias Nyman, xen-devel, linux-usb, linux-kernel

When running as a dom0 guest on Xen, check if the USB3 debug
capability is enabled before xHCI reset, suspend, and resume. If it
is, call xen_dbgp_reset_prep() to notify Xen that it is unsafe to touch
MMIO registers until the next xen_dbgp_external_startup().

This notification allows Xen to avoid undefined behavior resulting
from MMIO access when the host controller's CNR bit is set or when
the device transitions to D3hot.

Signed-off-by: Connor Davis <connojdavis@gmail.com>
---
 drivers/usb/host/xhci-dbgcap.h |  6 ++++
 drivers/usb/host/xhci.c        | 57 ++++++++++++++++++++++++++++++++++
 drivers/usb/host/xhci.h        |  1 +
 3 files changed, 64 insertions(+)

diff --git a/drivers/usb/host/xhci-dbgcap.h b/drivers/usb/host/xhci-dbgcap.h
index c70b78d504eb..24784b82a840 100644
--- a/drivers/usb/host/xhci-dbgcap.h
+++ b/drivers/usb/host/xhci-dbgcap.h
@@ -227,4 +227,10 @@ static inline int xhci_dbc_resume(struct xhci_hcd *xhci)
 	return 0;
 }
 #endif /* CONFIG_USB_XHCI_DBGCAP */
+
+#ifdef CONFIG_XEN_DOM0
+int xen_dbgp_reset_prep(struct usb_hcd *hcd);
+int xen_dbgp_external_startup(struct usb_hcd *hcd);
+#endif /* CONFIG_XEN_DOM0 */
+
 #endif /* __LINUX_XHCI_DBGCAP_H */
diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
index ca9385d22f68..afe44169183f 100644
--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -37,6 +37,57 @@ static unsigned long long quirks;
 module_param(quirks, ullong, S_IRUGO);
 MODULE_PARM_DESC(quirks, "Bit flags for quirks to be enabled as default");

+#ifdef CONFIG_XEN_DOM0
+#include <xen/xen.h>
+
+static void xhci_dbc_external_reset_prep(struct xhci_hcd *xhci)
+{
+	struct dbc_regs __iomem *regs;
+	void __iomem		*base;
+	int			dbc_cap;
+
+	if (!xen_initial_domain())
+		return;
+
+	base = &xhci->cap_regs->hc_capbase;
+	dbc_cap = xhci_find_next_ext_cap(base, 0, XHCI_EXT_CAPS_DEBUG);
+
+	if (!dbc_cap)
+		return;
+
+	xhci->external_dbc = 0;
+	regs = base + dbc_cap;
+
+	if (readl(&regs->control) & DBC_CTRL_DBC_ENABLE) {
+		if (xen_dbgp_reset_prep(xhci_to_hcd(xhci)))
+			xhci_dbg_trace(xhci, trace_xhci_dbg_init,
+					"// Failed to reset external DBC");
+		else {
+			xhci->external_dbc = 1;
+			xhci_dbg_trace(xhci, trace_xhci_dbg_init,
+					"// Completed reset of external DBC");
+		}
+	}
+}
+
+static void xhci_dbc_external_reset_done(struct xhci_hcd *xhci)
+{
+	if (!xen_initial_domain() || !xhci->external_dbc)
+		return;
+
+	if (xen_dbgp_external_startup(xhci_to_hcd(xhci)))
+		xhci->external_dbc = 0;
+}
+#else
+static void xhci_dbc_external_reset_prep(struct xhci_hcd *xhci)
+{
+}
+
+static void xhci_dbc_external_reset_done(struct xhci_hcd *xhci)
+{
+}
+#endif
+
 static bool td_on_ring(struct xhci_td *td, struct xhci_ring *ring)
 {
 	struct xhci_segment *seg = ring->first_seg;
@@ -180,6 +231,8 @@ int xhci_reset(struct xhci_hcd *xhci)
 		return 0;
 	}

+	xhci_dbc_external_reset_prep(xhci);
+
 	xhci_dbg_trace(xhci, trace_xhci_dbg_init, "// Reset the HC");
 	command = readl(&xhci->op_regs->command);
 	command |= CMD_RESET;
@@ -211,6 +264,8 @@ int xhci_reset(struct xhci_hcd *xhci)
 	 */
 	ret = xhci_handshake(&xhci->op_regs->status,
 			STS_CNR, 0, 10 * 1000 * 1000);
+	if (!ret)
+		xhci_dbc_external_reset_done(xhci);

 	xhci->usb2_rhub.bus_state.port_c_suspend = 0;
 	xhci->usb2_rhub.bus_state.suspended_ports = 0;
@@ -991,6 +1046,7 @@ int xhci_suspend(struct xhci_hcd *xhci, bool do_wakeup)
 		return 0;

 	xhci_dbc_suspend(xhci);
+	xhci_dbc_external_reset_prep(xhci);

 	/* Don't poll the roothubs on bus suspend. */
 	xhci_dbg(xhci, "%s: stopping port polling.\n", __func__);
@@ -1225,6 +1281,7 @@ int xhci_resume(struct xhci_hcd *xhci, bool hibernated)
 	spin_unlock_irq(&xhci->lock);

 	xhci_dbc_resume(xhci);
+	xhci_dbc_external_reset_done(xhci);

  done:
 	if (retval == 0) {
diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h
index 2595a8f057c4..61d8efc9eef2 100644
--- a/drivers/usb/host/xhci.h
+++ b/drivers/usb/host/xhci.h
@@ -1920,6 +1920,7 @@ struct xhci_hcd {
 	struct list_head	regset_list;

 	void			*dbc;
+	int			external_dbc;
 	/* platform-specific data -- must come last */
 	unsigned long		priv[] __aligned(sizeof(s64));
 };
--
2.31.1



^ permalink raw reply	[flat|nested] 11+ messages in thread

* Re: [PATCH 2/3] xen: Export dbgp functions when CONFIG_XEN_DOM0 is enabled
  2021-05-12  0:18 ` [PATCH 2/3] xen: Export dbgp functions when CONFIG_XEN_DOM0 is enabled Connor Davis
@ 2021-05-12  5:41   ` Juergen Gross
  2021-05-12 15:01     ` Connor Davis
  2021-05-12 13:54   ` Boris Ostrovsky
  1 sibling, 1 reply; 11+ messages in thread
From: Juergen Gross @ 2021-05-12  5:41 UTC (permalink / raw)
  To: Connor Davis, Boris Ostrovsky, Stefano Stabellini; +Cc: xen-devel, linux-kernel


[-- Attachment #1.1.1: Type: text/plain, Size: 335 bytes --]

On 12.05.21 02:18, Connor Davis wrote:
> Export xen_dbgp_reset_prep and xen_dbgp_external_startup
> when CONFIG_XEN_DOM0 is defined. This allows use of these symbols
> even if CONFIG_EARLY_PRINK_DBGP is defined.
> 
> Signed-off-by: Connor Davis <connojdavis@gmail.com>

Acked-by: Juergen Gross <jgross@suse.com>


Juergen


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^ permalink raw reply	[flat|nested] 11+ messages in thread

* Re: [PATCH 3/3] usb: xhci: Notify xen when DbC is unsafe to use
  2021-05-12  0:18 ` [PATCH 3/3] usb: xhci: Notify xen when DbC is unsafe to use Connor Davis
@ 2021-05-12  7:03   ` Greg Kroah-Hartman
  2021-05-12 14:59     ` Connor Davis
  0 siblings, 1 reply; 11+ messages in thread
From: Greg Kroah-Hartman @ 2021-05-12  7:03 UTC (permalink / raw)
  To: Connor Davis; +Cc: Mathias Nyman, xen-devel, linux-usb, linux-kernel

On Tue, May 11, 2021 at 06:18:21PM -0600, Connor Davis wrote:
> When running as a dom0 guest on Xen, check if the USB3 debug
> capability is enabled before xHCI reset, suspend, and resume. If it
> is, call xen_dbgp_reset_prep() to notify Xen that it is unsafe to touch
> MMIO registers until the next xen_dbgp_external_startup().
> 
> This notification allows Xen to avoid undefined behavior resulting
> from MMIO access when the host controller's CNR bit is set or when
> the device transitions to D3hot.
> 
> Signed-off-by: Connor Davis <connojdavis@gmail.com>
> ---
>  drivers/usb/host/xhci-dbgcap.h |  6 ++++
>  drivers/usb/host/xhci.c        | 57 ++++++++++++++++++++++++++++++++++
>  drivers/usb/host/xhci.h        |  1 +
>  3 files changed, 64 insertions(+)
> 
> diff --git a/drivers/usb/host/xhci-dbgcap.h b/drivers/usb/host/xhci-dbgcap.h
> index c70b78d504eb..24784b82a840 100644
> --- a/drivers/usb/host/xhci-dbgcap.h
> +++ b/drivers/usb/host/xhci-dbgcap.h
> @@ -227,4 +227,10 @@ static inline int xhci_dbc_resume(struct xhci_hcd *xhci)
>  	return 0;
>  }
>  #endif /* CONFIG_USB_XHCI_DBGCAP */
> +
> +#ifdef CONFIG_XEN_DOM0
> +int xen_dbgp_reset_prep(struct usb_hcd *hcd);
> +int xen_dbgp_external_startup(struct usb_hcd *hcd);
> +#endif /* CONFIG_XEN_DOM0 */
> +
>  #endif /* __LINUX_XHCI_DBGCAP_H */
> diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
> index ca9385d22f68..afe44169183f 100644
> --- a/drivers/usb/host/xhci.c
> +++ b/drivers/usb/host/xhci.c
> @@ -37,6 +37,57 @@ static unsigned long long quirks;
>  module_param(quirks, ullong, S_IRUGO);
>  MODULE_PARM_DESC(quirks, "Bit flags for quirks to be enabled as default");
> 
> +#ifdef CONFIG_XEN_DOM0
> +#include <xen/xen.h>

<snip>

Can't this #ifdef stuff go into a .h file?

thanks,

greg k-h


^ permalink raw reply	[flat|nested] 11+ messages in thread

* Re: [PATCH 2/3] xen: Export dbgp functions when CONFIG_XEN_DOM0 is enabled
  2021-05-12  0:18 ` [PATCH 2/3] xen: Export dbgp functions when CONFIG_XEN_DOM0 is enabled Connor Davis
  2021-05-12  5:41   ` Juergen Gross
@ 2021-05-12 13:54   ` Boris Ostrovsky
  2021-05-12 14:58     ` Connor Davis
  1 sibling, 1 reply; 11+ messages in thread
From: Boris Ostrovsky @ 2021-05-12 13:54 UTC (permalink / raw)
  To: Connor Davis, Juergen Gross, Stefano Stabellini; +Cc: xen-devel, linux-kernel


On 5/11/21 8:18 PM, Connor Davis wrote:
> Export xen_dbgp_reset_prep and xen_dbgp_external_startup
> when CONFIG_XEN_DOM0 is defined. This allows use of these symbols
> even if CONFIG_EARLY_PRINK_DBGP is defined.
>
> Signed-off-by: Connor Davis <connojdavis@gmail.com>
> ---
>  drivers/xen/dbgp.c | 2 +-


Unrelated to your patch but since you are fixing things around that file --- should we return -EPERM in xen_dbgp_op() when !xen_initial_domain()?



-boris



^ permalink raw reply	[flat|nested] 11+ messages in thread

* Re: [PATCH 2/3] xen: Export dbgp functions when CONFIG_XEN_DOM0 is enabled
  2021-05-12 13:54   ` Boris Ostrovsky
@ 2021-05-12 14:58     ` Connor Davis
  2021-05-12 15:18       ` Boris Ostrovsky
  0 siblings, 1 reply; 11+ messages in thread
From: Connor Davis @ 2021-05-12 14:58 UTC (permalink / raw)
  To: Boris Ostrovsky
  Cc: Juergen Gross, Stefano Stabellini, xen-devel, linux-kernel

On May 12, 21, Boris Ostrovsky wrote:
>
> On 5/11/21 8:18 PM, Connor Davis wrote:
> > Export xen_dbgp_reset_prep and xen_dbgp_external_startup
> > when CONFIG_XEN_DOM0 is defined. This allows use of these symbols
> > even if CONFIG_EARLY_PRINK_DBGP is defined.
> >
> > Signed-off-by: Connor Davis <connojdavis@gmail.com>
> > ---
> >  drivers/xen/dbgp.c | 2 +-
>
>
> Unrelated to your patch but since you are fixing things around that file --- should we return -EPERM in xen_dbgp_op() when !xen_initial_domain()?

Yeah looks like it. That would make patch 3 simpler too.
Do you want me to add a patch that fixes that up?

>
> -boris
>

Thanks,
Connor


^ permalink raw reply	[flat|nested] 11+ messages in thread

* Re: [PATCH 3/3] usb: xhci: Notify xen when DbC is unsafe to use
  2021-05-12  7:03   ` Greg Kroah-Hartman
@ 2021-05-12 14:59     ` Connor Davis
  0 siblings, 0 replies; 11+ messages in thread
From: Connor Davis @ 2021-05-12 14:59 UTC (permalink / raw)
  To: Greg Kroah-Hartman; +Cc: Mathias Nyman, xen-devel, linux-usb, linux-kernel

On May 12, 21, Greg Kroah-Hartman wrote:
> On Tue, May 11, 2021 at 06:18:21PM -0600, Connor Davis wrote:
> > When running as a dom0 guest on Xen, check if the USB3 debug
> > capability is enabled before xHCI reset, suspend, and resume. If it
> > is, call xen_dbgp_reset_prep() to notify Xen that it is unsafe to touch
> > MMIO registers until the next xen_dbgp_external_startup().
> >
> > This notification allows Xen to avoid undefined behavior resulting
> > from MMIO access when the host controller's CNR bit is set or when
> > the device transitions to D3hot.
> >
> > Signed-off-by: Connor Davis <connojdavis@gmail.com>
> > ---
> >  drivers/usb/host/xhci-dbgcap.h |  6 ++++
> >  drivers/usb/host/xhci.c        | 57 ++++++++++++++++++++++++++++++++++
> >  drivers/usb/host/xhci.h        |  1 +
> >  3 files changed, 64 insertions(+)
> >
> > diff --git a/drivers/usb/host/xhci-dbgcap.h b/drivers/usb/host/xhci-dbgcap.h
> > index c70b78d504eb..24784b82a840 100644
> > --- a/drivers/usb/host/xhci-dbgcap.h
> > +++ b/drivers/usb/host/xhci-dbgcap.h
> > @@ -227,4 +227,10 @@ static inline int xhci_dbc_resume(struct xhci_hcd *xhci)
> >  	return 0;
> >  }
> >  #endif /* CONFIG_USB_XHCI_DBGCAP */
> > +
> > +#ifdef CONFIG_XEN_DOM0
> > +int xen_dbgp_reset_prep(struct usb_hcd *hcd);
> > +int xen_dbgp_external_startup(struct usb_hcd *hcd);
> > +#endif /* CONFIG_XEN_DOM0 */
> > +
> >  #endif /* __LINUX_XHCI_DBGCAP_H */
> > diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
> > index ca9385d22f68..afe44169183f 100644
> > --- a/drivers/usb/host/xhci.c
> > +++ b/drivers/usb/host/xhci.c
> > @@ -37,6 +37,57 @@ static unsigned long long quirks;
> >  module_param(quirks, ullong, S_IRUGO);
> >  MODULE_PARM_DESC(quirks, "Bit flags for quirks to be enabled as default");
> >
> > +#ifdef CONFIG_XEN_DOM0
> > +#include <xen/xen.h>
>
> <snip>
>
> Can't this #ifdef stuff go into a .h file?
>

Yep, will clean that up in v2.

> thanks,
>
> greg k-h

Thanks,
Connor


^ permalink raw reply	[flat|nested] 11+ messages in thread

* Re: [PATCH 2/3] xen: Export dbgp functions when CONFIG_XEN_DOM0 is enabled
  2021-05-12  5:41   ` Juergen Gross
@ 2021-05-12 15:01     ` Connor Davis
  0 siblings, 0 replies; 11+ messages in thread
From: Connor Davis @ 2021-05-12 15:01 UTC (permalink / raw)
  To: Juergen Gross
  Cc: Boris Ostrovsky, Stefano Stabellini, xen-devel, linux-kernel

On May 12, 21, Juergen Gross wrote:
> On 12.05.21 02:18, Connor Davis wrote:
> > Export xen_dbgp_reset_prep and xen_dbgp_external_startup
> > when CONFIG_XEN_DOM0 is defined. This allows use of these symbols
> > even if CONFIG_EARLY_PRINK_DBGP is defined.
> >
> > Signed-off-by: Connor Davis <connojdavis@gmail.com>
>
> Acked-by: Juergen Gross <jgross@suse.com>

Thank you.

- Connor



^ permalink raw reply	[flat|nested] 11+ messages in thread

* Re: [PATCH 2/3] xen: Export dbgp functions when CONFIG_XEN_DOM0 is enabled
  2021-05-12 14:58     ` Connor Davis
@ 2021-05-12 15:18       ` Boris Ostrovsky
  0 siblings, 0 replies; 11+ messages in thread
From: Boris Ostrovsky @ 2021-05-12 15:18 UTC (permalink / raw)
  To: Connor Davis; +Cc: Juergen Gross, Stefano Stabellini, xen-devel, linux-kernel


On 5/12/21 10:58 AM, Connor Davis wrote:
> On May 12, 21, Boris Ostrovsky wrote:
>> Unrelated to your patch but since you are fixing things around that file --- should we return -EPERM in xen_dbgp_op() when !xen_initial_domain()?
> Yeah looks like it. That would make patch 3 simpler too.
> Do you want me to add a patch that fixes that up?


Yes, please.


-boris



^ permalink raw reply	[flat|nested] 11+ messages in thread

end of thread, other threads:[~2021-05-12 15:19 UTC | newest]

Thread overview: 11+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-05-12  0:18 [PATCH 0/3] Support xen-driven USB3 debug capability Connor Davis
2021-05-12  0:18 ` [PATCH 1/3] usb: early: Avoid using DbC if already enabled Connor Davis
2021-05-12  0:18 ` [PATCH 2/3] xen: Export dbgp functions when CONFIG_XEN_DOM0 is enabled Connor Davis
2021-05-12  5:41   ` Juergen Gross
2021-05-12 15:01     ` Connor Davis
2021-05-12 13:54   ` Boris Ostrovsky
2021-05-12 14:58     ` Connor Davis
2021-05-12 15:18       ` Boris Ostrovsky
2021-05-12  0:18 ` [PATCH 3/3] usb: xhci: Notify xen when DbC is unsafe to use Connor Davis
2021-05-12  7:03   ` Greg Kroah-Hartman
2021-05-12 14:59     ` Connor Davis

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