Commit Graph

7 Commits

Author SHA1 Message Date
Joao Martins
13ffb97a3b KVM: x86/xen: register shared_info page
Add KVM_XEN_ATTR_TYPE_SHARED_INFO to allow hypervisor to know where the
guest's shared info page is.

Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
2021-02-04 14:19:38 +00:00
David Woodhouse
a3833b81b0 KVM: x86/xen: latch long_mode when hypercall page is set up
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
2021-02-04 14:19:38 +00:00
Joao Martins
a76b9641ad KVM: x86/xen: add KVM_XEN_HVM_SET_ATTR/KVM_XEN_HVM_GET_ATTR
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>
2021-02-04 14:19:38 +00:00
David Woodhouse
7d6bbebb7b KVM: x86/xen: Add kvm_xen_enabled static key
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>
2021-02-04 14:19:38 +00:00
David Woodhouse
78e9878cb3 KVM: x86/xen: Move KVM_XEN_HVM_CONFIG handling to xen.c
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>
2021-02-04 14:19:38 +00:00
Joao Martins
79033bebf6 KVM: x86/xen: Fix coexistence of Xen and Hyper-V hypercalls
Disambiguate Xen vs. Hyper-V calls by adding 'orl $0x80000000, %eax'
at the start of the Hyper-V hypercall page when Xen hypercalls are
also enabled.

That bit is reserved in the Hyper-V ABI, and those hypercall numbers
will never be used by Xen (because it does precisely the same trick).

Switch to using kvm_vcpu_write_guest() while we're at it, instead of
open-coding it.

Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
2021-02-04 14:19:24 +00:00
Joao Martins
23200b7a30 KVM: x86/xen: intercept xen hypercalls if enabled
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>
2021-02-04 14:18:45 +00:00