KVM: x86/xen: handle PV spinlocks slowpath

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Add support for SCHEDOP_poll hypercall.

This implementation is optimized for polling for a single channel, which
is what Linux does. Polling for multiple channels is not especially
efficient (and has not been tested).

PV spinlocks slow path uses this hypercall, and explicitly crash if it's
not supported.

[ dwmw2: Rework to use kvm_vcpu_halt(), not supported for 32-bit guests ]

Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20220303154127.202856-17-dwmw2@infradead.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

...

This commit is contained in:

Boris Ostrovsky 2022-03-03 15:41:26 +00:00 • committed by Paolo Bonzini

parent 661a20fab7

commit 1a65105a5a

3 changed files with 165 additions and 2 deletions

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3

arch/x86/include/asm/kvm_host.h

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158

arch/x86/kvm/xen.c

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6

tools/testing/selftests/kvm/x86_64/xen_shinfo_test.c

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