kernel/git/stable/linux.git/Documentation/virt/kvm/msr.rst, branch master

Documentation: KVM: add separate directories for architecture-specific documentation

2022-03-29T17:21:20+00:00

ARM already has an arm/ subdirectory, but s390 and x86 do not even though they have a relatively large number of files specific to them. Create new directories in Documentation/virt/kvm for these two architectures as well. While at it, group the API documentation and the developer documentation in the table of contents. Signed-off-by: Paolo Bonzini Message-Id: <20220322110712.222449-2-pbonzini@redhat.com> Signed-off-by: Paolo Bonzini

KVM: X86: Introduce KVM_HC_MAP_GPA_RANGE hypercall

2021-06-17T18:25:39+00:00

This hypercall is used by the SEV guest to notify a change in the page encryption status to the hypervisor. The hypercall should be invoked only when the encryption attribute is changed from encrypted -> decrypted and vice versa. By default all guest pages are considered encrypted. The hypercall exits to userspace to manage the guest shared regions and integrate with the userspace VMM's migration code. Cc: Thomas Gleixner Cc: Ingo Molnar Cc: "H. Peter Anvin" Cc: Paolo Bonzini Cc: Joerg Roedel Cc: Borislav Petkov Cc: Tom Lendacky Cc: x86@kernel.org Cc: kvm@vger.kernel.org Cc: linux-kernel@vger.kernel.org Reviewed-by: Steve Rutherford Signed-off-by: Brijesh Singh Signed-off-by: Ashish Kalra Co-developed-by: Sean Christopherson Signed-off-by: Sean Christopherson Co-developed-by: Paolo Bonzini Signed-off-by: Paolo Bonzini Message-Id: <90778988e1ee01926ff9cac447aacb745f954c8c.1623174621.git.ashish.kalra@amd.com> Signed-off-by: Paolo Bonzini

KVM: x86: announce KVM_FEATURE_ASYNC_PF_INT

2020-06-01T08:26:08+00:00

Introduce new capability to indicate that KVM supports interrupt based delivery of 'page ready' APF events. This includes support for both MSR_KVM_ASYNC_PF_INT and MSR_KVM_ASYNC_PF_ACK. Signed-off-by: Vitaly Kuznetsov Message-Id: <20200525144125.143875-8-vkuznets@redhat.com> Signed-off-by: Paolo Bonzini

KVM: x86: acknowledgment mechanism for async pf page ready notifications

2020-06-01T08:26:08+00:00

If two page ready notifications happen back to back the second one is not delivered and the only mechanism we currently have is kvm_check_async_pf_completion() check in vcpu_run() loop. The check will only be performed with the next vmexit when it happens and in some cases it may take a while. With interrupt based page ready notification delivery the situation is even worse: unlike exceptions, interrupts are not handled immediately so we must check if the slot is empty. This is slow and unnecessary. Introduce dedicated MSR_KVM_ASYNC_PF_ACK MSR to communicate the fact that the slot is free and host should check its notification queue. Mandate using it for interrupt based 'page ready' APF event delivery. As kvm_check_async_pf_completion() is going away from vcpu_run() we need a way to communicate the fact that vcpu->async_pf.done queue has transitioned from empty to non-empty state. Introduce kvm_arch_async_page_present_queued() and KVM_REQ_APF_READY to do the job. Signed-off-by: Vitaly Kuznetsov Message-Id: <20200525144125.143875-7-vkuznets@redhat.com> Signed-off-by: Paolo Bonzini

KVM: x86: interrupt based APF 'page ready' event delivery

2020-06-01T08:26:07+00:00

Concerns were expressed around APF delivery via synthetic #PF exception as in some cases such delivery may collide with real page fault. For 'page ready' notifications we can easily switch to using an interrupt instead. Introduce new MSR_KVM_ASYNC_PF_INT mechanism and deprecate the legacy one. One notable difference between the two mechanisms is that interrupt may not get handled immediately so whenever we would like to deliver next event (regardless of its type) we must be sure the guest had read and cleared previous event in the slot. While on it, get rid on 'type 1/type 2' names for APF events in the documentation as they are causing confusion. Use 'page not present' and 'page ready' everywhere instead. Signed-off-by: Vitaly Kuznetsov Message-Id: <20200525144125.143875-6-vkuznets@redhat.com> Signed-off-by: Paolo Bonzini

docs: virt: Convert msr.txt to ReST format

2020-02-12T19:09:51+00:00

- Use document title markup; - Convert tables; - Add blank lines and adjust indentation. Signed-off-by: Mauro Carvalho Chehab Signed-off-by: Paolo Bonzini