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[PULL,23/24] kvm: i386: require KVM_CAP_SET_IDENTITY_MAP_ADDR

Message ID 20231025232718.89428-24-pbonzini@redhat.com
State New
Headers show
Series [PULL,01/24] tests/tcg: fix out-of-bounds access in test-avx | expand

Commit Message

Paolo Bonzini Oct. 25, 2023, 11:27 p.m. UTC 
This was introduced in KVM in Linux 2.6.32, we can require it unconditionally.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 target/i386/kvm/kvm.c | 20 +++++++-------------
 1 file changed, 7 insertions(+), 13 deletions(-)
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Patch

diff --git a/target/i386/kvm/kvm.c b/target/i386/kvm/kvm.c
index d4bf327fa6f..e364b842e6d 100644
--- a/target/i386/kvm/kvm.c
+++ b/target/i386/kvm/kvm.c
@@ -99,6 +99,7 @@  const KVMCapabilityInfo kvm_arch_required_capabilities[] = {
     KVM_CAP_INFO(X86_ROBUST_SINGLESTEP),
     KVM_CAP_INFO(MCE),
     KVM_CAP_INFO(ADJUST_CLOCK),
+    KVM_CAP_INFO(SET_IDENTITY_MAP_ADDR),
     KVM_CAP_LAST_INFO
 };
 
@@ -2600,20 +2601,13 @@  int kvm_arch_init(MachineState *ms, KVMState *s)
      * In order to use vm86 mode, an EPT identity map and a TSS  are needed.
      * Since these must be part of guest physical memory, we need to allocate
      * them, both by setting their start addresses in the kernel and by
-     * creating a corresponding e820 entry. We need 4 pages before the BIOS.
-     *
-     * Older KVM versions may not support setting the identity map base. In
-     * that case we need to stick with the default, i.e. a 256K maximum BIOS
-     * size.
+     * creating a corresponding e820 entry. We need 4 pages before the BIOS,
+     * so this value allows up to 16M BIOSes.
      */
-    if (kvm_check_extension(s, KVM_CAP_SET_IDENTITY_MAP_ADDR)) {
-        /* Allows up to 16M BIOSes. */
-        identity_base = 0xfeffc000;
-
-        ret = kvm_vm_ioctl(s, KVM_SET_IDENTITY_MAP_ADDR, &identity_base);
-        if (ret < 0) {
-            return ret;
-        }
+    identity_base = 0xfeffc000;
+    ret = kvm_vm_ioctl(s, KVM_SET_IDENTITY_MAP_ADDR, &identity_base);
+    if (ret < 0) {
+        return ret;
     }
 
     /* Set TSS base one page after EPT identity map. */