cachepc

commit d16af2b7f9b0026e2776237dd0ea673d88531e7d
parent 82d56ef77c114ac0b375fef04cea3a50f10f1843
Author: Louis Burda <quent.burda@gmail.com>
Date:   Tue, 22 Nov 2022 15:34:51 +0100

Add program to verify SVME bit is set during VMRUN

Diffstat:
M
Makefile
 | 
1
+
M
cachepc/cachepc.h
 | 
2
+-
M
cachepc/kvm.c
 | 
25
+++++++++++++++++++++++++
M
cachepc/mmu.c
 | 
2
--
M
cachepc/uapi.h
 | 
1
+
M
test/.gitignore
 | 
1
+
A
test/readsvme.c
 | 
26
++++++++++++++++++++++++++

7 files changed, 55 insertions(+), 3 deletions(-)
diff --git a/Makefile b/Makefile
@@ -4,6 +4,7 @@ PWD := $(shell pwd)
 TARGETS = build test/eviction test/access test/kvm test/sev test/sev-es test/sevstep 
 TARGETS += test/aes-detect_guest test/aes-detect_host
 TARGETS += test/access-detect_guest test/access-detect_host
+TARGETS += test/readsvme
 
 CFLAGS = -I . -I test -Wunused-variable -Wunknown-pragmas
 
diff --git a/cachepc/cachepc.h b/cachepc/cachepc.h
@@ -278,7 +278,7 @@ cachepc_read_pmc(uint64_t event)
 		: "=a" (lo), "=d" (hi)
 		: "c"(event)
 	);
-	res = ((uint64_t) hi << 32) | (uint64_t) lo;
+	res = (((uint64_t) hi) << 32) | (uint64_t) lo;
 
 	cachepc_mfence();
 	cachepc_cpuid();
diff --git a/cachepc/kvm.c b/cachepc/kvm.c
@@ -541,6 +541,29 @@ cachepc_kvm_vmsa_read_ioctl(void __user *arg_user)
 }
 
 int
+cachepc_kvm_svme_read_ioctl(void __user *arg_user)
+{
+	uint32_t lo, hi;
+	uint64_t res;
+	uint32_t svme;
+
+	if (!arg_user) return -EINVAL;
+
+	asm volatile (
+		"rdmsr"
+		: "=a" (lo), "=d" (hi)
+		: "c" (0xC0000080)
+	);
+	res = (((uint64_t) hi) << 32) | (uint64_t) lo;
+
+	svme = (res >> 12) & 1;
+	if (copy_to_user(arg_user, &svme, sizeof(uint32_t)))
+		return -EFAULT;
+
+	return 0;
+}
+
+int
 cachepc_kvm_track_all_ioctl(void __user *arg_user)
 {
 	struct kvm_vcpu *vcpu;
@@ -658,6 +681,8 @@ cachepc_kvm_ioctl(struct file *file, unsigned int ioctl, unsigned long arg)
 		return cachepc_kvm_track_mode_ioctl(arg_user);
 	case KVM_CPC_VMSA_READ:
 		return cachepc_kvm_vmsa_read_ioctl(arg_user);
+	case KVM_CPC_SVME_READ:
+		return cachepc_kvm_svme_read_ioctl(arg_user);
 	case KVM_CPC_TRACK_PAGE:
 		return cachepc_kvm_track_page_ioctl(arg_user);
 	case KVM_CPC_TRACK_ALL:
diff --git a/cachepc/mmu.c b/cachepc/mmu.c
@@ -26,8 +26,6 @@ cachepc_page_fault_handle(struct kvm_vcpu *vcpu,
 			/* first fault from instruction fetch */
 			pr_warn("CachePC: Got inst fault gfn:%llu err:%u\n",
 				fault->gfn, fault->error_code);
-			//if (!inst_fetch)
-			//	pr_err("CachePC: Expected inst fault but was not on fetch\n");
 
 			cachepc_inst_fault_gfn = fault->gfn;
 			cachepc_inst_fault_err = fault->error_code;
diff --git a/cachepc/uapi.h b/cachepc/uapi.h
@@ -45,6 +45,7 @@
 #define KVM_CPC_SINGLE_STEP _IO(KVMIO, 0x29)
 #define KVM_CPC_TRACK_MODE _IOWR(KVMIO, 0x2A, __u32)
 #define KVM_CPC_VMSA_READ _IOR(KVMIO, 0x2B, __u64)
+#define KVM_CPC_SVME_READ _IOR(KVMIO, 0x2C, __u32)
 
 #define KVM_CPC_TRACK_PAGE _IOWR(KVMIO, 0x30, struct cpc_track_config)
 #define KVM_CPC_TRACK_ALL _IOWR(KVMIO, 0x31, __u64)
diff --git a/test/.gitignore b/test/.gitignore
@@ -9,3 +9,4 @@ aes-detect_guest
 aes-detect_host
 access-detect_guest
 access-detect_host
+readsvme
diff --git a/test/readsvme.c b/test/readsvme.c
@@ -0,0 +1,26 @@
+#include "cachepc/uapi.h"
+
+#include <sys/ioctl.h>
+#include <err.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+int
+main(int argc, const char **argv)
+{
+	uint32_t svme;
+	int kvm_fd;
+
+	kvm_fd = open("/dev/kvm", O_RDWR);
+	if (kvm_fd < 0) err(1, "open /dev/kvm");
+
+	if (ioctl(kvm_fd, KVM_CPC_SVME_READ, &svme))
+		err(1, "ioctl SVME_READ");
+
+	printf("%u\n", svme);
+
+	close(kvm_fd);
+}