x86/fpu/xstate: Introduce XSAVES supervisor states (71581eef) · Commits · 戴 / test

arch/x86/kernel/fpu/xstate.c

+19 −9

Original line number	Diff line number	Diff line
		@@ -228,13 +228,14 @@ void fpu__init_cpu_xstate(void)
		* states can be set here.
		*/
		xsetbv(XCR_XFEATURE_ENABLED_MASK, xfeatures_mask_user());
		}

		/*
		* Note that in the future we will likely need a pair of
		* functions here: one for user xstates and the other for
		* system xstates. For now, they are the same.
		* MSR_IA32_XSS sets supervisor states managed by XSAVES.
		*/
		if (boot_cpu_has(X86_FEATURE_XSAVES))
		wrmsrl(MSR_IA32_XSS, xfeatures_mask_supervisor());
		}

		static bool xfeature_enabled(enum xfeature xfeature)
		{
		return xfeatures_mask_all & BIT_ULL(xfeature);
		@@ -625,9 +626,6 @@ static void do_extra_xstate_size_checks(void)
		* the size of the user states. If we use it to size a buffer
		* that we use 'XSAVES' on, we could potentially overflow the
		* buffer because 'XSAVES' saves system states too.
		*
		* Note that we do not currently set any bits on IA32_XSS so
		* 'XCR0 \| IA32_XSS == XCR0' for now.
		*/
		static unsigned int __init get_xsaves_size(void)
		{
		@@ -750,7 +748,12 @@ void __init fpu__init_system_xstate(void)
		cpuid_count(XSTATE_CPUID, 0, &eax, &ebx, &ecx, &edx);
		xfeatures_mask_all = eax + ((u64)edx << 32);

		/* Place supervisor features in xfeatures_mask_all here */
		/*
		* Find supervisor xstates supported by the processor.
		*/
		cpuid_count(XSTATE_CPUID, 1, &eax, &ebx, &ecx, &edx);
		xfeatures_mask_all \|= ecx + ((u64)edx << 32);

		if ((xfeatures_mask_user() & XFEATURE_MASK_FPSSE) != XFEATURE_MASK_FPSSE) {
		/*
		* This indicates that something really unexpected happened
		@@ -810,6 +813,13 @@ void fpu__resume_cpu(void)
		*/
		if (boot_cpu_has(X86_FEATURE_XSAVE))
		xsetbv(XCR_XFEATURE_ENABLED_MASK, xfeatures_mask_user());

		/*
		* Restore IA32_XSS. The same CPUID bit enumerates support
		* of XSAVES and MSR_IA32_XSS.
		*/
		if (boot_cpu_has(X86_FEATURE_XSAVES))
		wrmsrl(MSR_IA32_XSS, xfeatures_mask_supervisor());
		}

		/*

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