On 2/4/19 5:49 AM, David Gibson wrote: > On Wed, Jan 23, 2019 at 05:56:26PM +0100, Cédric Le Goater wrote: >> On 1/22/19 6:14 AM, Paul Mackerras wrote: >>> On Mon, Jan 07, 2019 at 07:43:20PM +0100, Cédric Le Goater wrote: >>>> The ESB MMIO region controls the interrupt sources of the guest. QEMU >>>> will query an fd (GET_ESB_FD ioctl) and map this region at a specific >>>> address for the guest to use. The guest will obtain this information >>>> using the H_INT_GET_SOURCE_INFO hcall. To inform KVM of the address >>>> setting used by QEMU, add a VC_BASE control to the KVM XIVE device >>> >>> This needs a little more explanation. I *think* the only way this >>> gets used is that it gets returned to the guest by the new >>> hypercalls. If that is indeed the case it would be useful to mention >>> that in the patch description, because otherwise taking a value that >>> userspace provides and which looks like it is an address, and not >>> doing any validation on it, looks a bit scary. >> >> I think we have solved this problem in another email thread. >> >> The H_INT_GET_SOURCE_INFO hcall does not need to be implemented in KVM >> as all the source information should already be available in QEMU. In >> that case, there is no need to inform KVM of where the ESB pages are >> mapped in the guest address space. So we don't need that extra control >> on the KVM device. This is good news. > > Ah, good to hear. I thought this looked strange. yes. I didn't know which path to choose between HV real mode, HV, QEMU. It's clarified now. But now, we have nested, and this is adding quite a bit of strangeness to the hcall possibilities. C.
