> -----Original Message----- > From: Xen-devel <[email protected]> On Behalf Of Roger > Pau Monne > Sent: 30 September 2019 14:32 > To: [email protected] > Cc: Andrew Cooper <[email protected]>; Paul Durrant <[email protected]>; > Wei Liu <[email protected]>; Jan > Beulich <[email protected]>; Roger Pau Monne <[email protected]> > Subject: [Xen-devel] [PATCH v3 01/10] ioreq: terminate cf8 handling at > hypervisor level > > Do not forward accesses to cf8 to external emulators, decoding of PCI > accesses is handled by Xen, and emulators can request handling of > config space accesses of devices using the provided ioreq interface. > > Fully terminate cf8 accesses at the hypervisor level, by improving the > existing hvm_access_cf8 helper to also handle register reads, and > always return X86EMUL_OKAY in order to terminate the emulation. > > Note that without this change in the absence of some external emulator > that catches accesses to cf8 read requests to the register would > misbehave, as the ioreq internal handler did not handle those. > > Signed-off-by: Roger Pau Monné <[email protected]>
Reviewed-by: Paul Durrant <[email protected]> > --- > Changes since v2: > - Allow ioreq servers to map 0xcf8 and 0xcfc, even if those are > handled by the hypervisor. > > Changes since v1: > - New in this version. > --- > xen/arch/x86/hvm/ioreq.c | 10 +++++++--- > 1 file changed, 7 insertions(+), 3 deletions(-) > > diff --git a/xen/arch/x86/hvm/ioreq.c b/xen/arch/x86/hvm/ioreq.c > index d347144096..5e503ce498 100644 > --- a/xen/arch/x86/hvm/ioreq.c > +++ b/xen/arch/x86/hvm/ioreq.c > @@ -1518,11 +1518,15 @@ static int hvm_access_cf8( > { > struct domain *d = current->domain; > > - if ( dir == IOREQ_WRITE && bytes == 4 ) > + if ( bytes != 4 ) > + return X86EMUL_OKAY; > + > + if ( dir == IOREQ_WRITE ) > d->arch.hvm.pci_cf8 = *val; > + else > + *val = d->arch.hvm.pci_cf8; > > - /* We always need to fall through to the catch all emulator */ > - return X86EMUL_UNHANDLEABLE; > + return X86EMUL_OKAY; > } > > void hvm_ioreq_init(struct domain *d) > -- > 2.23.0 > > > _______________________________________________ > Xen-devel mailing list > [email protected] > https://lists.xenproject.org/mailman/listinfo/xen-devel _______________________________________________ Xen-devel mailing list [email protected] https://lists.xenproject.org/mailman/listinfo/xen-devel
