fix(pci): disable decoding while sizing BARs

[stlankes]

Determining the size of a BAR writes all-ones into it and restores the previous value afterwards. While decoding is enabled, the device decodes those intermediate values as real addresses and relocates itself. For a passed-through device the host follows that relocation and tries to map the BAR outside of the guest, which aborts the VM:

kvm_set_user_memory_region: KVM_SET_USER_MEMORY_REGION failed,
slot=5, start=0xfffffffffe000000, size=0x400000: Invalid argument

Disable decoding around the probe, as the PCI specification requires, and route the informational bus dump through get_bar so that it is covered as well.

[github-actions]

Benchmark Results

Details

Benchmark	Current: 3431433	Previous: 2e23902	Performance Ratio
startup_benchmark Build Time	79.65 s	80.34 s	0.99 ❗
startup_benchmark File Size	0.76 MB	0.80 MB	0.96 ❗
Startup Time - 1 core	0.77 s (±0.03 s)	0.75 s (±0.02 s)	1.03
Startup Time - 2 cores	0.76 s (±0.03 s)	0.74 s (±0.02 s)	1.04
Startup Time - 4 cores	0.77 s (±0.02 s)	0.74 s (±0.02 s)	1.03
multithreaded_benchmark Build Time	81.37 s	82.11 s	0.99 ❗
multithreaded_benchmark File Size	0.88 MB	0.86 MB	1.02 ❗
Multithreaded Pi Efficiency - 2 Threads	86.35 % (±6.66 %)	85.89 % (±6.61 %)	1.01
Multithreaded Pi Efficiency - 4 Threads	42.31 % (±2.96 %)	43.43 % (±2.56 %)	0.97
Multithreaded Pi Efficiency - 8 Threads	25.03 % (±1.26 %)	25.76 % (±1.53 %)	0.97
micro_benchmarks Build Time	77.18 s	80.40 s	0.96 ❗
micro_benchmarks File Size	0.88 MB	0.86 MB	1.02 ❗
Scheduling time - 1 thread	63.46 ticks (±2.15 ticks)	62.65 ticks (±4.06 ticks)	1.01
Scheduling time - 2 threads	34.06 ticks (±3.01 ticks)	34.08 ticks (±4.10 ticks)	1.00
Micro - Time for syscall (getpid)	4.26 ticks (±0.68 ticks)	3.45 ticks (±0.58 ticks)	1.23
Memcpy speed - (built_in) block size 4096	82787.16 MByte/s (±57393.30 MByte/s)	82448.38 MByte/s (±56997.13 MByte/s)	1.00
Memcpy speed - (built_in) block size 1048576	30541.03 MByte/s (±24585.39 MByte/s)	30585.98 MByte/s (±24707.84 MByte/s)	1.00
Memcpy speed - (built_in) block size 16777216	29202.03 MByte/s (±24025.37 MByte/s)	26340.06 MByte/s (±21720.96 MByte/s)	1.11
Memset speed - (built_in) block size 4096	83099.66 MByte/s (±57608.79 MByte/s)	82292.76 MByte/s (±56891.50 MByte/s)	1.01
Memset speed - (built_in) block size 1048576	31262.48 MByte/s (±25011.06 MByte/s)	31323.85 MByte/s (±25145.86 MByte/s)	1.00
Memset speed - (built_in) block size 16777216	29980.66 MByte/s (±24480.94 MByte/s)	27104.68 MByte/s (±22209.94 MByte/s)	1.11
Memcpy speed - (rust) block size 4096	72916.78 MByte/s (±50985.04 MByte/s)	74097.96 MByte/s (±51811.44 MByte/s)	0.98
Memcpy speed - (rust) block size 1048576	30389.03 MByte/s (±24568.10 MByte/s)	30361.60 MByte/s (±24602.37 MByte/s)	1.00
Memcpy speed - (rust) block size 16777216	29434.68 MByte/s (±24224.32 MByte/s)	27625.34 MByte/s (±22806.88 MByte/s)	1.07
Memset speed - (rust) block size 4096	73380.01 MByte/s (±51330.57 MByte/s)	74373.47 MByte/s (±51976.48 MByte/s)	0.99
Memset speed - (rust) block size 1048576	31092.48 MByte/s (±25001.55 MByte/s)	31110.89 MByte/s (±25033.24 MByte/s)	1.00
Memset speed - (rust) block size 16777216	30192.72 MByte/s (±24658.07 MByte/s)	28386.93 MByte/s (±23265.03 MByte/s)	1.06
alloc_benchmarks Build Time	76.38 s	74.76 s	1.02 ❗
alloc_benchmarks File Size	0.84 MB	0.87 MB	0.96 ❗
Allocations - Allocation success	91.34 %	91.31 %	1.00 ❗
Allocations - Deallocation success	100.00 %	100.00 %	1
Allocations - Pre-fail Allocations	61.54 %	61.44 %	1.00 ❗
Allocations - Average Allocation time	2575.91 Ticks (±782.08 Ticks)	5860.58 Ticks (±98.43 Ticks)	0.44 ❗
Allocations - Average Allocation time (no fail)	3603.51 Ticks (±668.32 Ticks)	6554.81 Ticks (±92.86 Ticks)	0.55 ❗
Allocations - Average Deallocation time	714.50 Ticks (±213.43 Ticks)	1805.01 Ticks (±250.35 Ticks)	0.40 ❗
mutex_benchmark Build Time	80.73 s	79.82 s	1.01 ❗
mutex_benchmark File Size	0.88 MB	0.86 MB	1.02 ❗
Mutex Stress Test Average Time per Iteration - 1 Threads	12.10 ns (±0.30 ns)	12.10 ns (±0.41 ns)	1.00
Mutex Stress Test Average Time per Iteration - 2 Threads	39.80 ns (±2.42 ns)	40.26 ns (±1.68 ns)	0.99

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