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380b0e5e0e
Add a utility, proc_irq_set_smp_affinity(), to set the CPU affinity of a Linux host IRQ via the proc filesystem. Use smp_affinity_list instead of smp_affinity to avoid having to convert the single CPU to a bitmask. The helper will be used by the eventfd IRQ test to verify delivery of IRQs when the affinity is randomized/modified. Signed-off-by: Josh Hilke <jrhilke@google.com> [sean: make the utility self-contained, drop "list", massage changelog] Link: https://patch.msgid.link/20260626213534.3866178-11-seanjc@google.com Signed-off-by: Sean Christopherson <seanjc@google.com>
55 lines
1.2 KiB
C
55 lines
1.2 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#include "kvm_util.h"
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#include "test_util.h"
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#include "proc_util.h"
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static FILE *open_proc_interrupts(void)
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{
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FILE *fp;
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fp = fopen("/proc/interrupts", "r");
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TEST_ASSERT(fp, "fopen(/proc/interrupts) failed");
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return fp;
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}
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unsigned int vfio_msix_to_host_irq(const char *device_bdf, int msix)
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{
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char search_string[64];
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char line[4096];
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int irq = -1;
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FILE *fp;
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fp = open_proc_interrupts();
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snprintf(search_string, sizeof(search_string), "vfio-msix[%d]", msix);
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while (fgets(line, sizeof(line), fp)) {
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if (strstr(line, device_bdf) && strstr(line, search_string)) {
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TEST_ASSERT_EQ(1, sscanf(line, "%d:", &irq));
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break;
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}
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}
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fclose(fp);
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TEST_ASSERT(irq != -1, "Failed to locate IRQ for %s %s", device_bdf,
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search_string);
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return (unsigned int)irq;
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}
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void proc_irq_set_smp_affinity(unsigned int irq, int cpu)
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{
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char path[PATH_MAX];
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int r, fd;
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snprintf(path, sizeof(path), "/proc/irq/%u/smp_affinity_list", irq);
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fd = open(path, O_RDWR);
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TEST_ASSERT(fd >= 0, "Failed to open %s", path);
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r = dprintf(fd, "%d\n", cpu);
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TEST_ASSERT(r > 0, "Failed to affinitize IRQ-%u to CPU %d", irq, cpu);
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kvm_close(fd);
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}
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