[PATCH 4.18 42/79] x86/KVM/VMX: Separate the VMX AUTOLOAD guest/host number accounting

[Greg Kroah-Hartman]

4.18-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Konrad Rzeszutek Wilk <konrad.w...@oracle.com>

This allows to load a different number of MSRs depending on the context:
VMEXIT or VMENTER.

Signed-off-by: Konrad Rzeszutek Wilk <konrad.w...@oracle.com>
Signed-off-by: Thomas Gleixner <t...@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
 arch/x86/kvm/vmx.c |   29 +++++++++++++++++++----------
 1 file changed, 19 insertions(+), 10 deletions(-)

--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -2468,12 +2468,18 @@ static void clear_atomic_switch_msr(stru
        }
        i = find_msr(&m->guest, msr);
        if (i < 0)
-               return;
+               goto skip_guest;
        --m->guest.nr;
-       --m->host.nr;
        m->guest.val[i] = m->guest.val[m->guest.nr];
-       m->host.val[i] = m->host.val[m->host.nr];
        vmcs_write32(VM_ENTRY_MSR_LOAD_COUNT, m->guest.nr);
+
+skip_guest:
+       i = find_msr(&m->host, msr);
+       if (i < 0)
+               return;
+
+       --m->host.nr;
+       m->host.val[i] = m->host.val[m->host.nr];
        vmcs_write32(VM_EXIT_MSR_LOAD_COUNT, m->host.nr);
 }
 
@@ -2491,7 +2497,7 @@ static void add_atomic_switch_msr_specia
 static void add_atomic_switch_msr(struct vcpu_vmx *vmx, unsigned msr,
                                  u64 guest_val, u64 host_val)
 {
-       int i;
+       int i, j;
        struct msr_autoload *m = &vmx->msr_autoload;
 
        switch (msr) {
@@ -2527,21 +2533,24 @@ static void add_atomic_switch_msr(struct
        }
 
        i = find_msr(&m->guest, msr);
-       if (i == NR_AUTOLOAD_MSRS) {
+       j = find_msr(&m->host, msr);
+       if (i == NR_AUTOLOAD_MSRS || j == NR_AUTOLOAD_MSRS) {
                printk_once(KERN_WARNING "Not enough msr switch entries. "
                                "Can't add msr %x\n", msr);
                return;
-       } else if (i < 0) {
+       }
+       if (i < 0) {
                i = m->guest.nr++;
-               ++m->host.nr;
                vmcs_write32(VM_ENTRY_MSR_LOAD_COUNT, m->guest.nr);
+       }
+       if (j < 0) {
+               j = m->host.nr++;
                vmcs_write32(VM_EXIT_MSR_LOAD_COUNT, m->host.nr);
        }
-
        m->guest.val[i].index = msr;
        m->guest.val[i].value = guest_val;
-       m->host.val[i].index = msr;
-       m->host.val[i].value = host_val;
+       m->host.val[j].index = msr;
+       m->host.val[j].value = host_val;
 }
 
 static bool update_transition_efer(struct vcpu_vmx *vmx, int efer_offset)