cachepc

commit 9cce829d8a794848b0699c3f9a84b2a057221a90
parent 297900bdb5d58224bb1d65f5632a179de825c11d
Author: Louis Burda <quent.burda@gmail.com>
Date:   Thu, 29 Sep 2022 00:32:30 +0200

Adapt kernel module for sev-snp machine

Diffstat:
M
kmod/cachepc.c
 | 
4
++--
M
kmod/kvm.c
 | 
21
+++++++++++++++++++++

2 files changed, 23 insertions(+), 2 deletions(-)
diff --git a/kmod/cachepc.c b/kmod/cachepc.c
@@ -16,14 +16,14 @@ static void build_randomized_list_for_cache_set(cache_ctx *ctx, cacheline **cach
 static cacheline **allocate_cache_ds(cache_ctx *ctx);
 static uint16_t get_virt_cache_set(cache_ctx *ctx, void *ptr);
 
-void
+void __attribute__((optimize(1))) // prevent instruction reordering
 cachepc_prime_vcall(uintptr_t ret, cacheline *cl)
 {
 	cachepc_prime(cl);
 	asm volatile ("mov %0, %%rax; jmp *%%rax" : : "r"(ret) : "rax");
 }
 
-void
+void __attribute__((optimize(1))) // prevent instruction reordering
 cachepc_probe_vcall(uintptr_t ret, cacheline *cl)
 {
 	cachepc_probe(cl);
diff --git a/kmod/kvm.c b/kmod/kvm.c
@@ -69,6 +69,26 @@ cachepc_kvm_proc_write(struct file *file, const char *buf, size_t buflen, loff_t
 	return 0;
 }
 
+loff_t
+cachepc_kvm_proc_lseek(struct file *file, loff_t off, int mode)
+{
+	switch (mode) {
+	case SEEK_SET:
+		file->f_pos = off;
+		break;
+	case SEEK_CUR:
+		file->f_pos += off;
+		break;
+	case SEEK_END:
+		file->f_pos = cachepc_msrmts_count * sizeof(uint16_t) + off;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return file->f_pos;
+}
+
 void
 cachepc_kvm_prime_probe_test(void *p)
 {
@@ -355,6 +375,7 @@ cachepc_kvm_init(void)
 	cachepc_proc_ops.proc_open = cachepc_kvm_proc_open;
 	cachepc_proc_ops.proc_read = cachepc_kvm_proc_read;
 	cachepc_proc_ops.proc_write = cachepc_kvm_proc_write;
+	cachepc_proc_ops.proc_lseek = cachepc_kvm_proc_lseek;
 	cachepc_proc_ops.proc_release = cachepc_kvm_proc_close;
 	cachepc_proc_ops.proc_ioctl = cachepc_kvm_ioctl;
 	proc_create("cachepc", 0644, NULL, &cachepc_proc_ops);