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path: root/arch/x86/kvm/xen.c
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2021-02-09KVM: x86/xen: Use hva_t for holding hypercall page addressSean Christopherson
Use hva_t, a.k.a. unsigned long, for the local variable that holds the hypercall page address. On 32-bit KVM, gcc complains about using a u64 due to the implicit cast from a 64-bit value to a 32-bit pointer. arch/x86/kvm/xen.c: In function ‘kvm_xen_write_hypercall_page’: arch/x86/kvm/xen.c:300:22: error: cast to pointer from integer of different size [-Werror=int-to-pointer-cast] 300 | page = memdup_user((u8 __user *)blob_addr, PAGE_SIZE); Cc: Joao Martins <joao.m.martins@oracle.com> Cc: David Woodhouse <dwmw@amazon.co.uk> Fixes: 23200b7a30de ("KVM: x86/xen: intercept xen hypercalls if enabled") Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20210208201502.1239867-1-seanjc@google.com> Acked-by: David Woodhouse <dwmw@amazon.co.uk> Reviewed-by: Joao Martins <joao.m.martins@oracle.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-02-09KVM: x86/xen: Remove extra unlock in kvm_xen_hvm_set_attr()David Woodhouse
This accidentally ended up locking and then immediately unlocking kvm->lock at the beginning of the function. Fix it. Fixes: a76b9641ad1c ("KVM: x86/xen: add KVM_XEN_HVM_SET_ATTR/KVM_XEN_HVM_GET_ATTR") Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> Message-Id: <20210208232326.1830370-2-dwmw2@infradead.org> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-02-04KVM: x86/xen: Add event channel interrupt vector upcallDavid Woodhouse
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>
2021-02-04KVM: x86/xen: register vcpu time info regionJoao Martins
Allow the Xen emulated guest the ability to register secondary vcpu time information. On Xen guests this is used in order to be mapped to userspace and hence allow vdso gettimeofday to work. Signed-off-by: Joao Martins <joao.m.martins@oracle.com> Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
2021-02-04KVM: x86/xen: setup pvclock updatesJoao Martins
Parameterise kvm_setup_pvclock_page() a little bit so that it can be invoked for different gfn_to_hva_cache structures, and with different offsets. Then we can invoke it for the normal KVM pvclock and also for the Xen one in the vcpu_info. Signed-off-by: Joao Martins <joao.m.martins@oracle.com> Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
2021-02-04KVM: x86/xen: register vcpu infoJoao Martins
The vcpu info supersedes the per vcpu area of the shared info page and the guest vcpus will use this instead. Signed-off-by: Joao Martins <joao.m.martins@oracle.com> Signed-off-by: Ankur Arora <ankur.a.arora@oracle.com> Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
2021-02-04KVM: x86/xen: Add KVM_XEN_VCPU_SET_ATTR/KVM_XEN_VCPU_GET_ATTRDavid Woodhouse
This will be used for per-vCPU setup such as runstate and vcpu_info. Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
2021-02-04KVM: x86/xen: update wallclock regionJoao Martins
Wallclock on Xen is written in the shared_info page. To that purpose, export kvm_write_wall_clock() and pass on the GPA of its location to populate the shared_info wall clock data. Signed-off-by: Joao Martins <joao.m.martins@oracle.com> Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
2021-02-04KVM: x86/xen: register shared_info pageJoao Martins
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>
2021-02-04KVM: x86/xen: latch long_mode when hypercall page is set upDavid Woodhouse
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
2021-02-04KVM: x86/xen: add KVM_XEN_HVM_SET_ATTR/KVM_XEN_HVM_GET_ATTRJoao Martins
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>
2021-02-04KVM: x86/xen: Add kvm_xen_enabled static keyDavid Woodhouse
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>
2021-02-04KVM: x86/xen: Move KVM_XEN_HVM_CONFIG handling to xen.cDavid Woodhouse
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>
2021-02-04KVM: x86/xen: Fix coexistence of Xen and Hyper-V hypercallsJoao Martins
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>
2021-02-04KVM: x86/xen: intercept xen hypercalls if enabledJoao Martins
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>