On 06/12/2022 04:33, Demi Marie Obenour wrote: > This avoids it being a magic constant that is difficult for humans to > decode. Use a _Static_assert to check that the old and new values are > identical. > > Signed-off-by: Demi Marie Obenour <d...@invisiblethingslab.com> > --- > xen/arch/x86/include/asm/processor.h | 22 +++++++++++++++++++++- > 1 file changed, 21 insertions(+), 1 deletion(-) > > diff --git a/xen/arch/x86/include/asm/processor.h > b/xen/arch/x86/include/asm/processor.h > index > 8e2816fae9b97bd4e153a30cc3802971fe0355af..64b75e444947c64e2e5eba457deec92a873d7a63 > 100644 > --- a/xen/arch/x86/include/asm/processor.h > +++ b/xen/arch/x86/include/asm/processor.h > @@ -92,13 +92,33 @@ > X86_EFLAGS_NT|X86_EFLAGS_DF|X86_EFLAGS_IF| \ > X86_EFLAGS_TF) > > +/* Individual entries in IA32_CR_PAT */ > +#define MSR_PAT_UC _AC(0x00, ULL) > +#define MSR_PAT_WC _AC(0x01, ULL) > +#define MSR_PAT_RESERVED_1 _AC(0x02, ULL) > +#define MSR_PAT_RESERVED_2 _AC(0x03, ULL) > +#define MSR_PAT_WT _AC(0x04, ULL) > +#define MSR_PAT_WP _AC(0x05, ULL) > +#define MSR_PAT_WB _AC(0x06, ULL) > +#define MSR_PAT_UCM _AC(0x07, ULL)
This isn't really correct. Constants for MSRs typically live in msr-index.h, but these are architectural x86 memory types. These ought be #define X86_MT_$X ... (skipping the two reserved values) in x86-defns.h, and the PAT_TYPE_*, MTRR_TYPE_* and EPT_EMT_* constants want removing. There are two minor restrictions (EPT can't have UCM, MTRR can't have WC), but they are all operating in terms of architectural memory type values, and the code ought to reflect this. > + > /* > * Host IA32_CR_PAT value to cover all memory types. This is not the default > * MSR_PAT value, and is an ABI with PV guests. > */ > -#define XEN_MSR_PAT _AC(0x050100070406, ULL) > +#define XEN_MSR_PAT (MSR_PAT_WB << 0x00 | \ > + MSR_PAT_WT << 0x08 | \ > + MSR_PAT_UCM << 0x10 | \ > + MSR_PAT_UC << 0x18 | \ > + MSR_PAT_WC << 0x20 | \ > + MSR_PAT_WP << 0x28 | \ > + MSR_PAT_UC << 0x30 | \ > + MSR_PAT_UC << 0x38 | \ > + 0) > > #ifndef __ASSEMBLY__ > +_Static_assert(XEN_MSR_PAT == 0x050100070406ULL, > + "wrong XEN_MSR_PAT breaks PV guests"); This wants to be in the build_assertions() that you introduce in the next patch, and a BUILD_BUG_ON(). We still support compilers which don't know _Static_assert(). ~Andrew
