[PATCH] x86/hyperv: Fix hv_get/set_register for nested bringup

From: Nuno Das Neves
Date: Thu Feb 09 2023 - 17:03:02 EST


hv_get_nested_reg only translates SINT0, resulting in the wrong sint
being registered by nested vmbus.
Fix the issue with new utility function hv_is_sint_reg.
While at it, improve clarity of hv_set_non_nested_register and hv_is_synic_reg.

Signed-off-by: Nuno Das Neves <nunodasneves@xxxxxxxxxxxxxxxxxxx>
---
arch/x86/include/asm/mshyperv.h | 11 +++++++----
arch/x86/kernel/cpu/mshyperv.c | 8 ++++----
2 files changed, 11 insertions(+), 8 deletions(-)

diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h
index 9ae1a344536b..684c547c1cca 100644
--- a/arch/x86/include/asm/mshyperv.h
+++ b/arch/x86/include/asm/mshyperv.h
@@ -225,10 +225,13 @@ extern bool hv_isolation_type_snp(void);

static inline bool hv_is_synic_reg(unsigned int reg)
{
- if ((reg >= HV_REGISTER_SCONTROL) &&
- (reg <= HV_REGISTER_SINT15))
- return true;
- return false;
+ return (reg >= HV_REGISTER_SCONTROL) &&
+ (reg <= HV_REGISTER_SINT15);
+}
+static inline bool hv_is_sint_reg(unsigned int reg)
+{
+ return (reg >= HV_REGISTER_SINT0) &&
+ (reg <= HV_REGISTER_SINT15);
}

u64 hv_get_register(unsigned int reg);
diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c
index 0ceb6d1f9c3c..6bd344e1200f 100644
--- a/arch/x86/kernel/cpu/mshyperv.c
+++ b/arch/x86/kernel/cpu/mshyperv.c
@@ -44,6 +44,9 @@ struct ms_hyperv_info ms_hyperv;
#if IS_ENABLED(CONFIG_HYPERV)
static inline unsigned int hv_get_nested_reg(unsigned int reg)
{
+ if (hv_is_sint_reg(reg))
+ return reg - HV_REGISTER_SINT0 + HV_REGISTER_NESTED_SINT0;
+
switch (reg) {
case HV_REGISTER_SIMP:
return HV_REGISTER_NESTED_SIMP;
@@ -53,8 +56,6 @@ static inline unsigned int hv_get_nested_reg(unsigned int reg)
return HV_REGISTER_NESTED_SVERSION;
case HV_REGISTER_SCONTROL:
return HV_REGISTER_NESTED_SCONTROL;
- case HV_REGISTER_SINT0:
- return HV_REGISTER_NESTED_SINT0;
case HV_REGISTER_EOM:
return HV_REGISTER_NESTED_EOM;
default:
@@ -80,8 +81,7 @@ void hv_set_non_nested_register(unsigned int reg, u64 value)
hv_ghcb_msr_write(reg, value);

/* Write proxy bit via wrmsl instruction */
- if (reg >= HV_REGISTER_SINT0 &&
- reg <= HV_REGISTER_SINT15)
+ if (hv_is_sint_reg(reg))
wrmsrl(reg, value | 1 << 20);
} else {
wrmsrl(reg, value);
--
2.25.1