Add support for userspace MSR handling #241
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00xc
requested review from
acatangiu,
alxiord,
andreeaflorescu,
lauralt,
sameo,
roypat and
JonathanWoollett-Light
as code owners
roypat
previously approved these changes
Nov 15, 2023
|
Reordered |
roypat
previously approved these changes
Nov 16, 2023
|
Rebased on main, fixed conflicts and updated coverage. |
roypat
previously approved these changes
Nov 17, 2023
Add the appropriate types to allow for a VMM to intercept RDMSR and WRMSR instructions if access to an MSR is denied. By default, KVM injects #GP on denied accesses. To do this we need to add a new Cap variant which corresponds to KVM_CAP_X86_USER_SPACE_MSR, and two new VcpuExit variants that correspond to KVM_EXIT_X86_RDMSR and KVM_EXIT_X86_WRMSR respectively. We also need helper types to pass the relevant information about the exit to the VMM. Signed-off-by: Carlos López <[email protected]>
Add two tests to verify respectively that reading and writing to an invalid MSR trigger a VcpuExit. Signed-off-by: Carlos López <[email protected]>
Signed-off-by: Carlos López <[email protected]>
|
Rebased on main and fixed conflicts. |
roypat
approved these changes
Nov 21, 2023
|
Gentle ping for reviewers |
JonathanWoollett-Light
approved these changes
Nov 23, 2023
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Summary of the PR
Add support for userspace MSR handling. This is done by enabling the
KVM_CAP_X86_USER_SPACE_MSRcapability, which enables two new exits,KVM_EXIT_X86_RDMSRandKVM_EXIT_X86_WRMSR. This allows a VMM to intercept reads and writes to invalid MSRs instead of having KVM automatically inject a#GPinto the guest.This PR adds safe wrappers around
KVM_CAP_X86_USER_SPACE_MSR,KVM_EXIT_X86_RDMSRandKVM_EXIT_X86_WRMSR, some helper types and 2 relevant tests.Requirements
git commit -s), and the commitmessage has max 60 characters for the summary and max 75 characters for each
description line.
test.
Release" section of CHANGELOG.md (if no such section exists, please create one).
unsafecode is properly documented.