diff options
| author | Stanislav Kinsburskii <skinsburskii@linux.microsoft.com> | 2026-03-24 23:57:40 +0000 |
|---|---|---|
| committer | Wei Liu <wei.liu@kernel.org> | 2026-04-04 05:25:53 +0000 |
| commit | 16cbec24897624051b324aa3a85859c38ca65fde (patch) | |
| tree | ab66f0de1fbc4f76afb42f4f5f4af2fbffdeb156 /include/hyperv | |
| parent | b6422dff0e518245019233432b6bccfc30b73e2f (diff) | |
mshv: Fix infinite fault loop on permission-denied GPA intercepts
Prevent infinite fault loops when guests access memory regions without
proper permissions. Currently, mshv_handle_gpa_intercept() attempts to
remap pages for all faults on movable memory regions, regardless of
whether the access type is permitted. When a guest writes to a read-only
region, the remap succeeds but the region remains read-only, causing
immediate re-fault and spinning the vCPU indefinitely.
Validate intercept access type against region permissions before
attempting remaps. Reject writes to non-writable regions and executes to
non-executable regions early, returning false to let the VMM handle the
intercept appropriately.
This also closes a potential DoS vector where malicious guests could
intentionally trigger these fault loops to consume host resources.
Fixes: b9a66cd5ccbb ("mshv: Add support for movable memory regions")
Signed-off-by: Stanislav Kinsburskii <skinsburskii@linux.microsoft.com>
Reviewed-by: Anirudh Rayabharam (Microsoft) <anirudh@anirudhrb.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
Diffstat (limited to 'include/hyperv')
| -rw-r--r-- | include/hyperv/hvgdk_mini.h | 6 | ||||
| -rw-r--r-- | include/hyperv/hvhdk.h | 4 |
2 files changed, 8 insertions, 2 deletions
diff --git a/include/hyperv/hvgdk_mini.h b/include/hyperv/hvgdk_mini.h index 1823a290a7b7..f9600f87186a 100644 --- a/include/hyperv/hvgdk_mini.h +++ b/include/hyperv/hvgdk_mini.h @@ -1533,4 +1533,10 @@ struct hv_mmio_write_input { u8 data[HV_HYPERCALL_MMIO_MAX_DATA_LENGTH]; } __packed; +enum hv_intercept_access_type { + HV_INTERCEPT_ACCESS_READ = 0, + HV_INTERCEPT_ACCESS_WRITE = 1, + HV_INTERCEPT_ACCESS_EXECUTE = 2 +}; + #endif /* _HV_HVGDK_MINI_H */ diff --git a/include/hyperv/hvhdk.h b/include/hyperv/hvhdk.h index 245f3db53bf1..5e83d3714966 100644 --- a/include/hyperv/hvhdk.h +++ b/include/hyperv/hvhdk.h @@ -779,7 +779,7 @@ struct hv_x64_intercept_message_header { u32 vp_index; u8 instruction_length:4; u8 cr8:4; /* Only set for exo partitions */ - u8 intercept_access_type; + u8 intercept_access_type; /* enum hv_intercept_access_type */ union hv_x64_vp_execution_state execution_state; struct hv_x64_segment_register cs_segment; u64 rip; @@ -825,7 +825,7 @@ union hv_arm64_vp_execution_state { struct hv_arm64_intercept_message_header { u32 vp_index; u8 instruction_length; - u8 intercept_access_type; + u8 intercept_access_type; /* enum hv_intercept_access_type */ union hv_arm64_vp_execution_state execution_state; u64 pc; u64 cpsr; |