RE: [PATCH v5 2/7] hyperv: SVM enlightened TLB flush support flag
From: Michael Kelley <hidden>
Date: 2021-06-08 17:04:56
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From: Vineeth Pillai <redacted> Sent: Thursday, June 3, 2021 8:15 AM
Bit 22 of HYPERV_CPUID_FEATURES.EDX is specific to SVM and specifies support for enlightened TLB flush. With this enlightenment enabled, ASID invalidations flushes only gva->hpa entries. To flush TLB entries derived from NPT, hypercalls should be used
Nit: Isn't this "must be used"? "Should be used" sounds slightly optional, and I don't think that's the case.
quoted hunk ↗ jump to hunk
(HvFlushGuestPhysicalAddressSpace or HvFlushGuestPhysicalAddressList) Signed-off-by: Vineeth Pillai <redacted> --- arch/x86/include/asm/hyperv-tlfs.h | 9 +++++++++ 1 file changed, 9 insertions(+)diff --git a/arch/x86/include/asm/hyperv-tlfs.h b/arch/x86/include/asm/hyperv-tlfs.h index 606f5cc579b2..005bf14d0449 100644 --- a/arch/x86/include/asm/hyperv-tlfs.h +++ b/arch/x86/include/asm/hyperv-tlfs.h@@ -133,6 +133,15 @@ #define HV_X64_NESTED_GUEST_MAPPING_FLUSH BIT(18) #define HV_X64_NESTED_MSR_BITMAP BIT(19) +/* + * This is specific to AMD and specifies that enlightened TLB flush is + * supported. If guest opts in to this feature, ASID invalidations only + * flushes gva -> hpa mapping entries. To flush the TLB entries derived + * from NPT, hypercalls should be used (HvFlushGuestPhysicalAddressSpace
Same here regarding "should be used" vs. "must be used".
+ * or HvFlushGuestPhysicalAddressList). + */ +#define HV_X64_NESTED_ENLIGHTENED_TLB BIT(22) + /* HYPERV_CPUID_ISOLATION_CONFIG.EAX bits. */ #define HV_PARAVISOR_PRESENT BIT(0) -- 2.25.1
Reviewed-by: Michael Kelley <redacted>