summaryrefslogtreecommitdiff
path: root/arch/x86/xen/enlighten_pv.c
diff options
context:
space:
mode:
authorLinus Torvalds <torvalds@linux-foundation.org>2022-10-13 00:39:38 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2022-10-13 00:39:38 +0300
commit778ce723e93ee803ef5883619fe2391e00dbc209 (patch)
tree861f03223f34780fecce597b45588118236874d7 /arch/x86/xen/enlighten_pv.c
parent1440f576022887004f719883acb094e7e0dd4944 (diff)
parent7880672bdc975daa586e8256714d9906d30c615e (diff)
downloadlinux-778ce723e93ee803ef5883619fe2391e00dbc209.tar.xz
Merge tag 'for-linus-6.1-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip
Pull xen updates from Juergen Gross: - Some minor typo fixes - A fix of the Xen pcifront driver for supporting the device model to run in a Linux stub domain - A cleanup of the pcifront driver - A series to enable grant-based virtio with Xen on x86 - A cleanup of Xen PV guests to distinguish between safe and faulting MSR accesses - Two fixes of the Xen gntdev driver - Two fixes of the new xen grant DMA driver * tag 'for-linus-6.1-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip: xen: Kconfig: Fix spelling mistake "Maxmium" -> "Maximum" xen/pv: support selecting safe/unsafe msr accesses xen/pv: refactor msr access functions to support safe and unsafe accesses xen/pv: fix vendor checks for pmu emulation xen/pv: add fault recovery control to pmu msr accesses xen/virtio: enable grant based virtio on x86 xen/virtio: use dom0 as default backend for CONFIG_XEN_VIRTIO_FORCE_GRANT xen/virtio: restructure xen grant dma setup xen/pcifront: move xenstore config scanning into sub-function xen/gntdev: Accommodate VMA splitting xen/gntdev: Prevent leaking grants xen/virtio: Fix potential deadlock when accessing xen_grant_dma_devices xen/virtio: Fix n_pages calculation in xen_grant_dma_map(unmap)_page() xen/xenbus: Fix spelling mistake "hardward" -> "hardware" xen-pcifront: Handle missed Connected state
Diffstat (limited to 'arch/x86/xen/enlighten_pv.c')
-rw-r--r--arch/x86/xen/enlighten_pv.c101
1 files changed, 71 insertions, 30 deletions
diff --git a/arch/x86/xen/enlighten_pv.c b/arch/x86/xen/enlighten_pv.c
index 9b1a58dda935..f82857e48815 100644
--- a/arch/x86/xen/enlighten_pv.c
+++ b/arch/x86/xen/enlighten_pv.c
@@ -108,11 +108,21 @@ struct tls_descs {
*/
static DEFINE_PER_CPU(struct tls_descs, shadow_tls_desc);
+static __read_mostly bool xen_msr_safe = IS_ENABLED(CONFIG_XEN_PV_MSR_SAFE);
+
+static int __init parse_xen_msr_safe(char *str)
+{
+ if (str)
+ return strtobool(str, &xen_msr_safe);
+ return -EINVAL;
+}
+early_param("xen_msr_safe", parse_xen_msr_safe);
+
static void __init xen_pv_init_platform(void)
{
/* PV guests can't operate virtio devices without grants. */
if (IS_ENABLED(CONFIG_XEN_VIRTIO))
- virtio_set_mem_acc_cb(virtio_require_restricted_mem_acc);
+ virtio_set_mem_acc_cb(xen_virtio_restricted_mem_acc);
populate_extra_pte(fix_to_virt(FIX_PARAVIRT_BOOTMAP));
@@ -917,14 +927,18 @@ static void xen_write_cr4(unsigned long cr4)
native_write_cr4(cr4);
}
-static u64 xen_read_msr_safe(unsigned int msr, int *err)
+static u64 xen_do_read_msr(unsigned int msr, int *err)
{
- u64 val;
+ u64 val = 0; /* Avoid uninitialized value for safe variant. */
if (pmu_msr_read(msr, &val, err))
return val;
- val = native_read_msr_safe(msr, err);
+ if (err)
+ val = native_read_msr_safe(msr, err);
+ else
+ val = native_read_msr(msr);
+
switch (msr) {
case MSR_IA32_APICBASE:
val &= ~X2APIC_ENABLE;
@@ -933,23 +947,39 @@ static u64 xen_read_msr_safe(unsigned int msr, int *err)
return val;
}
-static int xen_write_msr_safe(unsigned int msr, unsigned low, unsigned high)
+static void set_seg(unsigned int which, unsigned int low, unsigned int high,
+ int *err)
{
- int ret;
- unsigned int which;
- u64 base;
+ u64 base = ((u64)high << 32) | low;
- ret = 0;
+ if (HYPERVISOR_set_segment_base(which, base) == 0)
+ return;
+ if (err)
+ *err = -EIO;
+ else
+ WARN(1, "Xen set_segment_base(%u, %llx) failed\n", which, base);
+}
+
+/*
+ * Support write_msr_safe() and write_msr() semantics.
+ * With err == NULL write_msr() semantics are selected.
+ * Supplying an err pointer requires err to be pre-initialized with 0.
+ */
+static void xen_do_write_msr(unsigned int msr, unsigned int low,
+ unsigned int high, int *err)
+{
switch (msr) {
- case MSR_FS_BASE: which = SEGBASE_FS; goto set;
- case MSR_KERNEL_GS_BASE: which = SEGBASE_GS_USER; goto set;
- case MSR_GS_BASE: which = SEGBASE_GS_KERNEL; goto set;
-
- set:
- base = ((u64)high << 32) | low;
- if (HYPERVISOR_set_segment_base(which, base) != 0)
- ret = -EIO;
+ case MSR_FS_BASE:
+ set_seg(SEGBASE_FS, low, high, err);
+ break;
+
+ case MSR_KERNEL_GS_BASE:
+ set_seg(SEGBASE_GS_USER, low, high, err);
+ break;
+
+ case MSR_GS_BASE:
+ set_seg(SEGBASE_GS_KERNEL, low, high, err);
break;
case MSR_STAR:
@@ -965,31 +995,42 @@ static int xen_write_msr_safe(unsigned int msr, unsigned low, unsigned high)
break;
default:
- if (!pmu_msr_write(msr, low, high, &ret))
- ret = native_write_msr_safe(msr, low, high);
+ if (!pmu_msr_write(msr, low, high, err)) {
+ if (err)
+ *err = native_write_msr_safe(msr, low, high);
+ else
+ native_write_msr(msr, low, high);
+ }
}
+}
- return ret;
+static u64 xen_read_msr_safe(unsigned int msr, int *err)
+{
+ return xen_do_read_msr(msr, err);
+}
+
+static int xen_write_msr_safe(unsigned int msr, unsigned int low,
+ unsigned int high)
+{
+ int err = 0;
+
+ xen_do_write_msr(msr, low, high, &err);
+
+ return err;
}
static u64 xen_read_msr(unsigned int msr)
{
- /*
- * This will silently swallow a #GP from RDMSR. It may be worth
- * changing that.
- */
int err;
- return xen_read_msr_safe(msr, &err);
+ return xen_do_read_msr(msr, xen_msr_safe ? &err : NULL);
}
static void xen_write_msr(unsigned int msr, unsigned low, unsigned high)
{
- /*
- * This will silently swallow a #GP from WRMSR. It may be worth
- * changing that.
- */
- xen_write_msr_safe(msr, low, high);
+ int err;
+
+ xen_do_write_msr(msr, low, high, xen_msr_safe ? &err : NULL);
}
/* This is called once we have the cpu_possible_mask */