From 9eb06ddea87c33163d1c60612652d280f4eb174a Mon Sep 17 00:00:00 2001 From: Andrea Arcangeli Date: Wed, 12 Feb 2014 13:30:18 +0100 Subject: fix guest physical bits to match host, to go beyond 1TB guests RH-Author: Andrea Arcangeli Message-id: <1392211818-14964-2-git-send-email-aarcange@redhat.com> Patchwork-id: 57245 O-Subject: [RHEL-7.0 qemu-kvm PATCH] fix guest physical bits to match host, to go beyond 1TB guests Bugzilla: 989677 RH-Acked-by: Paolo Bonzini RH-Acked-by: Andrew Jones RH-Acked-by: Marcelo Tosatti Without this patch the guest physical bits are advertised as 40, not 44 or more depending on the hardware capability of the host. That leads to guest kernel crashes with injection of page faults 9 (see oops: 0009) as bits above 40 in the guest pagetables are considered reserved. exregion-0206 [324572448] [17] ex_system_memory_space: System-Memory (width 32) R/W 0 Address=00000000FED00000 BUG: unable to handle kernel paging request at ffffc9006030e000 IP: [] acpi_ex_system_memory_space_handler+0x23e/0x2cb PGD e01f875067 PUD 1001f075067 PMD e0178d8067 PTE 80000000fed00173 Oops: 0009 [#1] SMP (see PUD with bit >=40 set) Signed-off-by: Andrea Arcangeli Reported-by: Chegu Vinod diff --git a/target-i386/cpu.c b/target-i386/cpu.c index af2bf48..8b3476c 100644 --- a/target-i386/cpu.c +++ b/target-i386/cpu.c @@ -2594,8 +2594,13 @@ void cpu_x86_cpuid(CPUX86State *env, uint32_t index, uint32_t count, /* XXX: This value must match the one used in the MMU code. */ if (env->features[FEAT_8000_0001_EDX] & CPUID_EXT2_LM) { /* 64 bit processor */ -/* XXX: The physical address space is limited to 42 bits in exec.c. */ *eax = 0x00003028; /* 48 bits virtual, 40 bits physical */ + if (kvm_enabled()) { + uint32_t _eax; + host_cpuid(0x80000000, 0, &_eax, NULL, NULL, NULL); + if (_eax >= 0x80000008) + host_cpuid(0x80000008, 0, eax, NULL, NULL, NULL); + } } else { if (env->features[FEAT_1_EDX] & CPUID_PSE36) { *eax = 0x00000024; /* 36 bits physical */