[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Qemu-devel] [PATCH v1 05/10] xen/pt: Remove XenPTReg->data field.
From: |
Konrad Rzeszutek Wilk |
Subject: |
Re: [Qemu-devel] [PATCH v1 05/10] xen/pt: Remove XenPTReg->data field. |
Date: |
Fri, 17 Jul 2015 12:48:41 -0400 |
User-agent: |
Mutt/1.5.23 (2014-03-12) |
On Fri, Jul 17, 2015 at 05:30:39PM +0100, Stefano Stabellini wrote:
> On Thu, 2 Jul 2015, Konrad Rzeszutek Wilk wrote:
> > We do not want to have two entries to cache the guest configuration
> > registers: XenPTReg->data and dev.config. Instead we want to use
> > only the dev.config.
> >
> > To do without much complications we rip out the ->data field
> > and replace it with an pointer to the dev.config. This way we
> > have the type-checking (uint8_t, uint16_t, etc) and as well
> > and pre-computed location.
> >
> > Alternatively we could compute the offset in dev.config by
> > using the XenPTRRegInfo and XenPTRegGroup every time but
> > this way we have the pre-computed values.
> >
> > Signed-off-by: Konrad Rzeszutek Wilk <address@hidden>
> > ---
> > hw/xen/xen_pt.h | 6 +++-
> > hw/xen/xen_pt_config_init.c | 73
> > +++++++++++++++++++++++++++------------------
> > 2 files changed, 49 insertions(+), 30 deletions(-)
> >
> > diff --git a/hw/xen/xen_pt.h b/hw/xen/xen_pt.h
> > index 09358b1..586d055 100644
> > --- a/hw/xen/xen_pt.h
> > +++ b/hw/xen/xen_pt.h
> > @@ -134,7 +134,11 @@ struct XenPTRegInfo {
> > struct XenPTReg {
> > QLIST_ENTRY(XenPTReg) entries;
> > XenPTRegInfo *reg;
> > - uint32_t data; /* emulated value */
> > + union {
> > + uint8_t *byte;
> > + uint16_t *word;
> > + uint32_t *dbword;
> > + } ptr; /* pointer to dev.config. */
>
> Nice (nasty?) trick. I would probably have just introduced a single
> pointer, but this might turn out to be better as it avoids the risk of
> merging bits that should be ignored.
Right, and also adds nice type-casting checks.
>
> However it should be half-word (uint16_t) and word (uint32_t).
OK.
- Re: [Qemu-devel] [PATCH v1 04/10] xen/pt: Use xen_host_pci_get_[byte, word, long] instead of xen_host_pci_get_long, (continued)
- [Qemu-devel] [PATCH v1 10/10] xen/pt: Check for return values for xen_host_pci_[get|set] in init, Konrad Rzeszutek Wilk, 2015/07/02
- [Qemu-devel] [PATCH v1 08/10] xen/pt: Make xen_pt_unregister_device idempotent, Konrad Rzeszutek Wilk, 2015/07/02
- [Qemu-devel] [PATCH v1 03/10] xen/pt: Check if reg->init function sets the 'data' past the reg->size, Konrad Rzeszutek Wilk, 2015/07/02
- [Qemu-devel] [PATCH v1 06/10] xen/pt: Log xen_host_pci_get in two init functions, Konrad Rzeszutek Wilk, 2015/07/02
- [Qemu-devel] [PATCH v1 05/10] xen/pt: Remove XenPTReg->data field., Konrad Rzeszutek Wilk, 2015/07/02
- [Qemu-devel] [PATCH v1 02/10] xen/pt: Sync up the dev.config and data values., Konrad Rzeszutek Wilk, 2015/07/02
- [Qemu-devel] [PATCH v1 09/10] xen/pt: Move bulk of xen_pt_unregister_device in its own routine., Konrad Rzeszutek Wilk, 2015/07/02
- [Qemu-devel] [PATCH v1 07/10] xen/pt: Log xen_host_pci_get/set errors in MSI code., Konrad Rzeszutek Wilk, 2015/07/02
- [Qemu-devel] [PATCH] Follow-on to Remove XenPTReg->data and use dev.config for guest configuration values., Konrad Rzeszutek Wilk, 2015/07/08