On 2014-04-18 02:35, Nadav Amit wrote:
> According to Intel specifications, PAE and non-PAE does not have any reserved
> bits. In long-mode, regardless to PCIDE, only the high bits (above the
> physical address) are reserved.
>
> Signed-off-by: Nadav Amit <namit@xxxxxxxxxxxxxxxxx>
> ---
> :100644 100644 7de069af.. e21aee9... M arch/x86/include/asm/kvm_host.h
> :100644 100644 205b17e... 1d60374... M arch/x86/kvm/emulate.c
> :100644 100644 8b8fc0b... f4d9839... M arch/x86/kvm/x86.c
> arch/x86/include/asm/kvm_host.h | 6 +-----
> arch/x86/kvm/emulate.c | 4 ----
> arch/x86/kvm/x86.c | 25 +++++--------------------
> 3 files changed, 6 insertions(+), 29 deletions(-)
>
> diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
> index 7de069af..e21aee9 100644
> --- a/arch/x86/include/asm/kvm_host.h
> +++ b/arch/x86/include/asm/kvm_host.h
> @@ -50,11 +50,7 @@
> | X86_CR0_ET | X86_CR0_NE | X86_CR0_WP | X86_CR0_AM \
> | X86_CR0_NW | X86_CR0_CD | X86_CR0_PG))
>
> -#define CR3_PAE_RESERVED_BITS ((X86_CR3_PWT | X86_CR3_PCD) - 1)
> -#define CR3_NONPAE_RESERVED_BITS ((PAGE_SIZE-1) & ~(X86_CR3_PWT | X86_CR3_PCD))
> -#define CR3_PCID_ENABLED_RESERVED_BITS 0xFFFFFF0000000000ULL
> -#define CR3_L_MODE_RESERVED_BITS (CR3_NONPAE_RESERVED_BITS | \
> - 0xFFFFFF0000000000ULL)
> +#define CR3_L_MODE_RESERVED_BITS 0xFFFFFF0000000000ULL
> #define CR4_RESERVED_BITS \
> (~(unsigned long)(X86_CR4_VME | X86_CR4_PVI | X86_CR4_TSD | X86_CR4_DE\
> | X86_CR4_PSE | X86_CR4_PAE | X86_CR4_MCE \
> diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
> index 205b17e..1d60374 100644
> --- a/arch/x86/kvm/emulate.c
> +++ b/arch/x86/kvm/emulate.c
> @@ -3386,10 +3386,6 @@ static int check_cr_write(struct x86_emulate_ctxt *ctxt)
> ctxt->ops->get_msr(ctxt, MSR_EFER, &efer);
> if (efer & EFER_LMA)
> rsvd = CR3_L_MODE_RESERVED_BITS;
> - else if (ctxt->ops->get_cr(ctxt, 4) & X86_CR4_PAE)
> - rsvd = CR3_PAE_RESERVED_BITS;
> - else if (ctxt->ops->get_cr(ctxt, 0) & X86_CR0_PG)
> - rsvd = CR3_NONPAE_RESERVED_BITS;
>
> if (new_val & rsvd)
> return emulate_gp(ctxt, 0);
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index 8b8fc0b..f4d9839 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -701,26 +701,11 @@ int kvm_set_cr3(struct kvm_vcpu *vcpu, unsigned long cr3)
> return 0;
> }
>
> - if (is_long_mode(vcpu)) {
> - if (kvm_read_cr4_bits(vcpu, X86_CR4_PCIDE)) {
> - if (cr3 & CR3_PCID_ENABLED_RESERVED_BITS)
> - return 1;
> - } else
> - if (cr3 & CR3_L_MODE_RESERVED_BITS)
> - return 1;
> - } else {
> - if (is_pae(vcpu)) {
> - if (cr3 & CR3_PAE_RESERVED_BITS)
> - return 1;
> - if (is_paging(vcpu) &&
> - !load_pdptrs(vcpu, vcpu->arch.walk_mmu, cr3))
> - return 1;
> - }
> - /*
> - * We don't check reserved bits in nonpae mode, because
> - * this isn't enforced, and VMware depends on this.
> - */
> - }
> + if (is_long_mode(vcpu) && (cr3 & CR3_L_MODE_RESERVED_BITS))
> + return 1;
> + if (is_pae(vcpu) && is_paging(vcpu) &&
> + !load_pdptrs(vcpu, vcpu->arch.walk_mmu, cr3))
> + return 1;
This is wrong: is_pae returns true in long mode, but we don't have valid
pdptrs then. Crashes my Jailhouse guest.
I suppose we need a patch on top as this is already in kvm.next, right?
Jan
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