Add a 2 byte pad to struct compat_vcpu_info so that the sum size of its
fields is actually 64 bytes. The effective size without the padding is
also 64 bytes due to the compiler aligning evtchn_pending_sel to a 4-byte
boundary, but depending on compiler alignment is subtle and unnecessary.
Opportunistically replace spaces with tables in the other fields.
Cc: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20210210182609.435200-6-seanjc@google.com>
Reviewed-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
It turns out that we can't handle event channels *entirely* in userspace
by delivering them as ExtINT, because KVM is a bit picky about when it
accepts ExtINT interrupts from a legacy PIC. The in-kernel local APIC
has to have LVT0 configured in APIC_MODE_EXTINT and unmasked, which
isn't necessarily the case for Xen guests especially on secondary CPUs.
To cope with this, add kvm_xen_get_interrupt() which checks the
evtchn_pending_upcall field in the Xen vcpu_info, and delivers the Xen
upcall vector (configured by KVM_XEN_ATTR_TYPE_UPCALL_VECTOR) if it's
set regardless of LAPIC LVT0 configuration. This gives us the minimum
support we need for completely userspace-based implementation of event
channels.
This does mean that vcpu_enter_guest() needs to check for the
evtchn_pending_upcall flag being set, because it can't rely on someone
having set KVM_REQ_EVENT unless we were to add some way for userspace to
do so manually.
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
There aren't a lot of differences for the things that the kernel needs
to care about, but there are a few.
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
This will be used to set up shared info pages etc.
Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
The code paths for Xen support are all fairly lightweight but if we hide
them behind this, they're even *more* lightweight for any system which
isn't actually hosting Xen guests.
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
This is already more complex than the simple memcpy it originally had.
Move it to xen.c with the rest of the Xen support.
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Add a new exit reason for emulator to handle Xen hypercalls.
Since this means KVM owns the ABI, dispense with the facility for the
VMM to provide its own copy of the hypercall pages; just fill them in
directly using VMCALL/VMMCALL as we do for the Hyper-V hypercall page.
This behaviour is enabled by a new INTERCEPT_HCALL flag in the
KVM_XEN_HVM_CONFIG ioctl structure, and advertised by the same flag
being returned from the KVM_CAP_XEN_HVM check.
Rename xen_hvm_config() to kvm_xen_write_hypercall_page() and move it
to the nascent xen.c while we're at it, and add a test case.
Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
