Re: [PATCH v3 3/4] Revert "xen: Introduce 'xen_nopv' to disable PV extensions for HVM guests."

From: Zhenzhong Duan
Date: Tue Jul 02 2019 - 00:38:51 EST

On 2019/7/2 11:48, Boris Ostrovsky wrote:
On Mon, Jul 01, 2019 at 10:20:27AM +0800, Zhenzhong Duan wrote:
This reverts commit 8d693b911bb9c57009c24cb1772d205b84c7985c.

Instead we use an unified parameter 'nopv' for all the hypervisor

Signed-off-by: Zhenzhong Duan<zhenzhong.duan@xxxxxxxxxx>
Reviewed-by: Juergen Gross<jgross@xxxxxxxx>
Cc: Boris Ostrovsky<boris.ostrovsky@xxxxxxxxxx>
Cc: Juergen Gross<jgross@xxxxxxxx>
Cc: Stefano Stabellini<sstabellini@xxxxxxxxxx>
Cc: Thomas Gleixner<tglx@xxxxxxxxxxxxx>
Cc: Ingo Molnar<mingo@xxxxxxxxxx>
Cc: Borislav Petkov<bp@xxxxxxxxx>
Documentation/admin-guide/kernel-parameters.txt | 4 ----
arch/x86/xen/enlighten_hvm.c | 12 +-----------
2 files changed, 1 insertion(+), 15 deletions(-)

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 21e08af..d5c3dcc 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -5251,10 +5251,6 @@
Disables the ticketlock slowpath using Xen PV
- xen_nopv [X86]
- Disables the PV optimizations forcing the HVM guest to
- run as generic HVM guest with no PV drivers.
So someone upgrades the kernel and suddenly things work differently?

At least there should be a warning that the option has been replaced
with 'nopv' (but I would actually keep this option working as well).

OK, I'll add new patch to map xen_nopv to nopv. So if 'xen_nopv' is used, we go

to the path for 'nopv'. I will be same effect.