[PATCH v2 11/15] KVM: VMX: Add vmx_setup_uret_msr() to handle lookup and swap

From: Sean Christopherson
Date: Wed Sep 23 2020 - 14:05:04 EST


Add vmx_setup_uret_msr() to wrap the lookup and manipulation of the uret
MSRs array during setup_msrs(). In addition to consolidating code, this
eliminates move_msr_up(), which while being a very literally description
of the function, isn't exacly helpful in understanding the net effect of
the code.

No functional change intended.

Signed-off-by: Sean Christopherson <sean.j.christopherson@xxxxxxxxx>
---
arch/x86/kvm/vmx/vmx.c | 49 ++++++++++++++++--------------------------
1 file changed, 18 insertions(+), 31 deletions(-)

diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index f3192855f0fb..93cf86672764 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -1685,12 +1685,15 @@ static void vmx_queue_exception(struct kvm_vcpu *vcpu)
vmx_clear_hlt(vcpu);
}

-/*
- * Swap MSR entry in host/guest MSR entry array.
- */
-static void move_msr_up(struct vcpu_vmx *vmx, int from, int to)
+static void vmx_setup_uret_msr(struct vcpu_vmx *vmx, unsigned int msr)
{
struct vmx_uret_msr tmp;
+ int from, to;
+
+ from = __vmx_find_uret_msr(vmx, msr);
+ if (from < 0)
+ return;
+ to = vmx->nr_active_uret_msrs++;

tmp = vmx->guest_uret_msrs[to];
vmx->guest_uret_msrs[to] = vmx->guest_uret_msrs[from];
@@ -1704,42 +1707,26 @@ static void move_msr_up(struct vcpu_vmx *vmx, int from, int to)
*/
static void setup_msrs(struct vcpu_vmx *vmx)
{
- int nr_active_uret_msrs, index;
-
- nr_active_uret_msrs = 0;
+ vmx->guest_uret_msrs_loaded = false;
+ vmx->nr_active_uret_msrs = 0;
#ifdef CONFIG_X86_64
/*
* The SYSCALL MSRs are only needed on long mode guests, and only
* when EFER.SCE is set.
*/
if (is_long_mode(&vmx->vcpu) && (vmx->vcpu.arch.efer & EFER_SCE)) {
- index = __vmx_find_uret_msr(vmx, MSR_STAR);
- if (index >= 0)
- move_msr_up(vmx, index, nr_active_uret_msrs++);
- index = __vmx_find_uret_msr(vmx, MSR_LSTAR);
- if (index >= 0)
- move_msr_up(vmx, index, nr_active_uret_msrs++);
- index = __vmx_find_uret_msr(vmx, MSR_SYSCALL_MASK);
- if (index >= 0)
- move_msr_up(vmx, index, nr_active_uret_msrs++);
+ vmx_setup_uret_msr(vmx, MSR_STAR);
+ vmx_setup_uret_msr(vmx, MSR_LSTAR);
+ vmx_setup_uret_msr(vmx, MSR_SYSCALL_MASK);
}
#endif
- if (update_transition_efer(vmx)) {
- index = __vmx_find_uret_msr(vmx, MSR_EFER);
- if (index >= 0)
- move_msr_up(vmx, index, nr_active_uret_msrs++);
- }
- if (guest_cpuid_has(&vmx->vcpu, X86_FEATURE_RDTSCP)) {
- index = __vmx_find_uret_msr(vmx, MSR_TSC_AUX);
- if (index >= 0)
- move_msr_up(vmx, index, nr_active_uret_msrs++);
- }
- index = __vmx_find_uret_msr(vmx, MSR_IA32_TSX_CTRL);
- if (index >= 0)
- move_msr_up(vmx, index, nr_active_uret_msrs++);
+ if (update_transition_efer(vmx))
+ vmx_setup_uret_msr(vmx, MSR_EFER);

- vmx->nr_active_uret_msrs = nr_active_uret_msrs;
- vmx->guest_uret_msrs_loaded = false;
+ if (guest_cpuid_has(&vmx->vcpu, X86_FEATURE_RDTSCP))
+ vmx_setup_uret_msr(vmx, MSR_TSC_AUX);
+
+ vmx_setup_uret_msr(vmx, MSR_IA32_TSX_CTRL);

if (cpu_has_vmx_msr_bitmap())
vmx_update_msr_bitmap(&vmx->vcpu);
--
2.28.0