Re: [Xen-devel] [PATCH v2 5/7] x86/xen: nopv parameter support for HVM guest

2019-06-26 Thread Juergen Gross 

On 26.06.19 10:56, Zhenzhong Duan wrote:


On 2019/6/25 20:31, Juergen Gross wrote:

On 24.06.19 14:02, Zhenzhong Duan wrote:

PVH guest needs PV extentions to work, so nopv parameter is ignored
for PVH but not for HVM guest.

In order for nopv parameter to take effect for HVM guest, we need to
distinguish between PVH and HVM guest early in hypervisor detection
code. By moving the detection of PVH in xen_platform_hvm(),
xen_pvh_domain() could be used for that purpose.

Signed-off-by: Zhenzhong Duan 
Cc: Boris Ostrovsky 
Cc: Juergen Gross 
Cc: Stefano Stabellini 
Cc: Thomas Gleixner 
Cc: Ingo Molnar 
Cc: Borislav Petkov 
Cc: xen-devel@lists.xenproject.org
---
  arch/x86/xen/enlighten_hvm.c | 18 --
  1 file changed, 12 insertions(+), 6 deletions(-)

diff --git a/arch/x86/xen/enlighten_hvm.c b/arch/x86/xen/enlighten_hvm.c
index 7fcb4ea..26939e7 100644
--- a/arch/x86/xen/enlighten_hvm.c
+++ b/arch/x86/xen/enlighten_hvm.c
@@ -25,6 +25,7 @@
  #include "mmu.h"
  #include "smp.h"
  +extern bool nopv;
  static unsigned long shared_info_pfn;
    void xen_hvm_init_shared_info(void)
@@ -226,20 +227,24 @@ static uint32_t __init xen_platform_hvm(void)
  if (xen_pv_domain())
  return 0;
  +#ifdef CONFIG_XEN_PVH
+    /* Test for PVH domain (PVH boot path taken overrides ACPI 
flags). */

+    if (!x86_platform.legacy.rtc && x86_platform.legacy.no_vga)
+    xen_pvh = true;


Sorry, this won't work, as ACPI tables are scanned only some time later.

Hmm, right. Thanks for point out.


You can test for xen_pvh being true here (for the case where the guest
has been booted via the Xen-PVH boot entry) and handle that case, but
the case of a PVH guest started via the normal boot entry (like via
grub2) and nopv specified is difficult. The only idea I have right now
would be to use another struct hypervisor_x86 for that case which will
only be used for Xen HVM/PVH _and_ nopv specified. It should be a copy
of the bare metal variant, but a special guest_late_init member issuing
a big fat warning in case PVH is being detected.


After that warning, I guess PVH will run into hang finally? If it's 
true, BUG() is better?


Adding another hypervisor_x86 is a bit redundant, I think of below change.

I'll test it tomorrow. But appreciate your suggestion whether it's 
feasible. Thanks


Yes, this seems to be a viable option.



--- a/arch/x86/xen/enlighten_hvm.c
+++ b/arch/x86/xen/enlighten_hvm.c
@@ -25,6 +25,7 @@
  #include "mmu.h"
  #include "smp.h"

+extern bool nopv;
  static unsigned long shared_info_pfn;

  void xen_hvm_init_shared_info(void)
@@ -221,11 +222,37 @@ bool __init xen_hvm_need_lapic(void)
     return true;
  }

+static __init void xen_hvm_nopv_guest_late_init(void)
+{
+#ifdef CONFIG_XEN_PVH
+   if (x86_platform.legacy.rtc || !x86_platform.legacy.no_vga)
+   return;
+
+   /* PVH detected. */
+   xen_pvh = true;
+
+   printk(KERN_CRIT "nopv parameter isn't supported in PVH guest\n");
+   BUG();
+#endif
+}
+
+
  static uint32_t __init xen_platform_hvm(void)
  {
     if (xen_pv_domain())
     return 0;

+   if (xen_pvh_domain() && nopv)
+   {
+   /* guest booting via the Xen-PVH boot entry goes here */


Mind adjusting indentation of that comment?

+   printk(KERN_INFO "nopv parameter is ignored in PVH 
guest\n");

+   }
+   else if (nopv)
+   {
+   /* guest booting via normal boot entry (like via grub2) goes 
here */


Same again?

With those corrected and no other changes you can add my:

Reviewed-by: Juergen Gross 


Juergen

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Re: [Xen-devel] [PATCH v2 5/7] x86/xen: nopv parameter support for HVM guest

2019-06-26 Thread Zhenzhong Duan 


On 2019/6/25 20:31, Juergen Gross wrote:

On 24.06.19 14:02, Zhenzhong Duan wrote:

PVH guest needs PV extentions to work, so nopv parameter is ignored
for PVH but not for HVM guest.

In order for nopv parameter to take effect for HVM guest, we need to
distinguish between PVH and HVM guest early in hypervisor detection
code. By moving the detection of PVH in xen_platform_hvm(),
xen_pvh_domain() could be used for that purpose.

Signed-off-by: Zhenzhong Duan 
Cc: Boris Ostrovsky 
Cc: Juergen Gross 
Cc: Stefano Stabellini 
Cc: Thomas Gleixner 
Cc: Ingo Molnar 
Cc: Borislav Petkov 
Cc: xen-devel@lists.xenproject.org
---
  arch/x86/xen/enlighten_hvm.c | 18 --
  1 file changed, 12 insertions(+), 6 deletions(-)

diff --git a/arch/x86/xen/enlighten_hvm.c b/arch/x86/xen/enlighten_hvm.c
index 7fcb4ea..26939e7 100644
--- a/arch/x86/xen/enlighten_hvm.c
+++ b/arch/x86/xen/enlighten_hvm.c
@@ -25,6 +25,7 @@
  #include "mmu.h"
  #include "smp.h"
  +extern bool nopv;
  static unsigned long shared_info_pfn;
    void xen_hvm_init_shared_info(void)
@@ -226,20 +227,24 @@ static uint32_t __init xen_platform_hvm(void)
  if (xen_pv_domain())
  return 0;
  +#ifdef CONFIG_XEN_PVH
+    /* Test for PVH domain (PVH boot path taken overrides ACPI 
flags). */

+    if (!x86_platform.legacy.rtc && x86_platform.legacy.no_vga)
+    xen_pvh = true;


Sorry, this won't work, as ACPI tables are scanned only some time later.

Hmm, right. Thanks for point out.


You can test for xen_pvh being true here (for the case where the guest
has been booted via the Xen-PVH boot entry) and handle that case, but
the case of a PVH guest started via the normal boot entry (like via
grub2) and nopv specified is difficult. The only idea I have right now
would be to use another struct hypervisor_x86 for that case which will
only be used for Xen HVM/PVH _and_ nopv specified. It should be a copy
of the bare metal variant, but a special guest_late_init member issuing
a big fat warning in case PVH is being detected.


After that warning, I guess PVH will run into hang finally? If it's 
true, BUG() is better?


Adding another hypervisor_x86 is a bit redundant, I think of below change.

I'll test it tomorrow. But appreciate your suggestion whether it's 
feasible. Thanks


--- a/arch/x86/xen/enlighten_hvm.c
+++ b/arch/x86/xen/enlighten_hvm.c
@@ -25,6 +25,7 @@
 #include "mmu.h"
 #include "smp.h"

+extern bool nopv;
 static unsigned long shared_info_pfn;

 void xen_hvm_init_shared_info(void)
@@ -221,11 +222,37 @@ bool __init xen_hvm_need_lapic(void)
    return true;
 }

+static __init void xen_hvm_nopv_guest_late_init(void)
+{
+#ifdef CONFIG_XEN_PVH
+   if (x86_platform.legacy.rtc || !x86_platform.legacy.no_vga)
+   return;
+
+   /* PVH detected. */
+   xen_pvh = true;
+
+   printk(KERN_CRIT "nopv parameter isn't supported in PVH guest\n");
+   BUG();
+#endif
+}
+
+
 static uint32_t __init xen_platform_hvm(void)
 {
    if (xen_pv_domain())
    return 0;

+   if (xen_pvh_domain() && nopv)
+   {
+   /* guest booting via the Xen-PVH boot entry goes here */
+   printk(KERN_INFO "nopv parameter is ignored in PVH 
guest\n");

+   }
+   else if (nopv)
+   {
+   /* guest booting via normal boot entry (like via grub2) goes here */
+   x86_init.hyper.guest_late_init = 
xen_hvm_nopv_guest_late_init;

+   return 0;
+   }
    return xen_cpuid_base();
 }

@@ -258,4 +285,5 @@ static __init void xen_hvm_guest_late_init(void)
    .init.init_mem_mapping  = xen_hvm_init_mem_mapping,
    .init.guest_late_init   = xen_hvm_guest_late_init,
    .runtime.pin_vcpu   = xen_pin_vcpu,
+   .ignore_nopv    = true,
 };


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Re: [Xen-devel] [PATCH v2 5/7] x86/xen: nopv parameter support for HVM guest

2019-06-25 Thread Juergen Gross 

On 24.06.19 14:02, Zhenzhong Duan wrote:

PVH guest needs PV extentions to work, so nopv parameter is ignored
for PVH but not for HVM guest.

In order for nopv parameter to take effect for HVM guest, we need to
distinguish between PVH and HVM guest early in hypervisor detection
code. By moving the detection of PVH in xen_platform_hvm(),
xen_pvh_domain() could be used for that purpose.

Signed-off-by: Zhenzhong Duan 
Cc: Boris Ostrovsky 
Cc: Juergen Gross 
Cc: Stefano Stabellini 
Cc: Thomas Gleixner 
Cc: Ingo Molnar 
Cc: Borislav Petkov 
Cc: xen-devel@lists.xenproject.org
---
  arch/x86/xen/enlighten_hvm.c | 18 --
  1 file changed, 12 insertions(+), 6 deletions(-)

diff --git a/arch/x86/xen/enlighten_hvm.c b/arch/x86/xen/enlighten_hvm.c
index 7fcb4ea..26939e7 100644
--- a/arch/x86/xen/enlighten_hvm.c
+++ b/arch/x86/xen/enlighten_hvm.c
@@ -25,6 +25,7 @@
  #include "mmu.h"
  #include "smp.h"
  
+extern bool nopv;

  static unsigned long shared_info_pfn;
  
  void xen_hvm_init_shared_info(void)

@@ -226,20 +227,24 @@ static uint32_t __init xen_platform_hvm(void)
if (xen_pv_domain())
return 0;
  
+#ifdef CONFIG_XEN_PVH

+   /* Test for PVH domain (PVH boot path taken overrides ACPI flags). */
+   if (!x86_platform.legacy.rtc && x86_platform.legacy.no_vga)
+   xen_pvh = true;


Sorry, this won't work, as ACPI tables are scanned only some time later.

You can test for xen_pvh being true here (for the case where the guest
has been booted via the Xen-PVH boot entry) and handle that case, but
the case of a PVH guest started via the normal boot entry (like via
grub2) and nopv specified is difficult. The only idea I have right now
would be to use another struct hypervisor_x86 for that case which will
only be used for Xen HVM/PVH _and_ nopv specified. It should be a copy
of the bare metal variant, but a special guest_late_init member issuing
a big fat warning in case PVH is being detected.


Juergen

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[Xen-devel] [PATCH v2 5/7] x86/xen: nopv parameter support for HVM guest

2019-06-25 Thread Zhenzhong Duan 
PVH guest needs PV extentions to work, so nopv parameter is ignored
for PVH but not for HVM guest.

In order for nopv parameter to take effect for HVM guest, we need to
distinguish between PVH and HVM guest early in hypervisor detection
code. By moving the detection of PVH in xen_platform_hvm(),
xen_pvh_domain() could be used for that purpose.

Signed-off-by: Zhenzhong Duan 
Cc: Boris Ostrovsky 
Cc: Juergen Gross 
Cc: Stefano Stabellini 
Cc: Thomas Gleixner 
Cc: Ingo Molnar 
Cc: Borislav Petkov 
Cc: xen-devel@lists.xenproject.org
---
 arch/x86/xen/enlighten_hvm.c | 18 --
 1 file changed, 12 insertions(+), 6 deletions(-)

diff --git a/arch/x86/xen/enlighten_hvm.c b/arch/x86/xen/enlighten_hvm.c
index 7fcb4ea..26939e7 100644
--- a/arch/x86/xen/enlighten_hvm.c
+++ b/arch/x86/xen/enlighten_hvm.c
@@ -25,6 +25,7 @@
 #include "mmu.h"
 #include "smp.h"
 
+extern bool nopv;
 static unsigned long shared_info_pfn;
 
 void xen_hvm_init_shared_info(void)
@@ -226,20 +227,24 @@ static uint32_t __init xen_platform_hvm(void)
if (xen_pv_domain())
return 0;
 
+#ifdef CONFIG_XEN_PVH
+   /* Test for PVH domain (PVH boot path taken overrides ACPI flags). */
+   if (!x86_platform.legacy.rtc && x86_platform.legacy.no_vga)
+   xen_pvh = true;
+#endif
+
+   if (!xen_pvh_domain() && nopv)
+   return 0;
+
return xen_cpuid_base();
 }
 
 static __init void xen_hvm_guest_late_init(void)
 {
 #ifdef CONFIG_XEN_PVH
-   /* Test for PVH domain (PVH boot path taken overrides ACPI flags). */
-   if (!xen_pvh &&
-   (x86_platform.legacy.rtc || !x86_platform.legacy.no_vga))
+   if (!xen_pvh)
return;
 
-   /* PVH detected. */
-   xen_pvh = true;
-
/* Make sure we don't fall back to (default) ACPI_IRQ_MODEL_PIC. */
if (!nr_ioapics && acpi_irq_model == ACPI_IRQ_MODEL_PIC)
acpi_irq_model = ACPI_IRQ_MODEL_PLATFORM;
@@ -258,4 +263,5 @@ static __init void xen_hvm_guest_late_init(void)
.init.init_mem_mapping  = xen_hvm_init_mem_mapping,
.init.guest_late_init   = xen_hvm_guest_late_init,
.runtime.pin_vcpu   = xen_pin_vcpu,
+   .ignore_nopv= true,
 };
-- 
1.8.3.1


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